* guide: max_validators
* guide: new approach
* restrict validators based on configurable max
* add some tests
* fix wasm build (Vec)
* clean up warnings
* add logging
* set validator indices in tests as well
* fix common tests
* Update runtime/parachains/src/util.rs
Co-authored-by: Andronik Ordian <write@reusable.software>
Co-authored-by: Andronik Ordian <write@reusable.software>
* add a magic number to backing statements encoded
* fix fallout in statement table
* fix some fallout in backing
* add magic to approval votes
* remove last references to Candidate variant
* update size-hint
* add tracing to approval voting
* notify if session info is not working
* add dispute period to chain specs
* propagate genesis session to parachains runtime
* use `on_genesis_session`
* protect against zero cores in computation
* tweak voting rule to be based off of best and add logs
* genesis configuration should use VRF slots only
* swallow more keystore errors
* add some docs
* make validation-worker args non-optional and update clap
* better tracing for bitfield signing and provisioner
* pass amount of bits in bitfields to inclusion instead of recomputing
* debug -> warn for some logs
* better tracing for availability recovery
* a little av-store tracing
* bridge: forward availability recovery messages
* add missing try_from impl
* some more tracing
* improve approval distribution tracing
* guide: hold onto pending approval messages until NewBlocks
* Hold onto pending approval messages until NewBlocks
* guide: adjust comment
* process all actions for one wakeup at a time
* vec
* fix network bridge test
* replace randomness-collective-flip with Babe
* remove PairNotFound
* Use KeyValueDB in approval-voting
* use KVDB instead of AuxStore
* add rocksdb to cargo toml
* add a Config struct
* create new DB in service
* fix dep for regular node
* make optional
* post merge fix
Co-authored-by: Andronik Ordian <write@reusable.software>
* guide changes for a fast-path requesting from backing validators
* add backing group to availability recovery message
* add new phase to interaction
* typos
* add full data messages
* handle new network messages
* dispatch full data requests
* cleanup
* check chunk index
* test for invalid recovery
* tests
* Typos.
* fix some grumbles
* be more explicit about error handling and control flow
* fast-path param
* use with_chunks_only in Service
Co-authored-by: Robert Klotzner <robert.klotzner@gmx.at>
* REVERT: comment out graphviz
* rewrite most of protocol-disputes
* write about conclusion and chain selection
* tie back in overview
* basic disputes module
* guide: InclusionInherent -> ParaInherent
* language
* add ParaInherentData type
* plug parainherentdata into provisioner
* provide_multi_dispute
* tweak
* inclusion pipeline logic for disputes
* be clearer about signature checking
* reject backing of disputed blocks
* some type rejigging
* known-disputes runtime API
* wire up inclusion
* Revert "REVERT: comment out graphviz"
This reverts commit 66203e362f7872cb413d258f74634a0aad70302b.
* timeouts
* include in initialization order
* address grumbles
* integrate approval voting into overseer
* expose public API and make keystore arc
* integrate overseer in service
* guide: `ApprovedAncestor` returns block number
* return block number along with hash from ApprovedAncestor
* introduce a voting rule for reporting on approval checking
* integrate the delay voting rule
* Rococo configuration
* fix compilation and add slack
* fix web-wasm build
* tweak parameterization
* migrate voting rules to asycn
* remove hack comment
* CancelProxy uses `reject_announcement` instead of `remove_announcement`
* add back remove_announcement
* Revert "add back remove_announcement"
This reverts commit 467b608a9d77c4303cb8daa33e8f14d391d6f417.
* skeleton
* skeleton aux-schema module
* start approval types
* start aux schema with aux store
* doc
* finish basic types
* start approval types
* doc
* finish basic types
* write out schema types
* add debug and codec impls to approval types
* add debug and codec impls to approval types
also add some key computation
* add debug and codec impls to approval types
* getters for block and candidate entries
* grumbles
* remove unused AssignmentId
* load_decode utility
* implement DB clearing
* function for adding new block entry to aux store
* start `canonicalize` implementation
* more skeleton
* finish implementing canonicalize
* tag TODO
* implement a test AuxStore
* add allow(unused)
* basic loading and deleting test
* block_entry test function
* add a test for `add_block_entry`
* ensure range is exclusive at end
* test clear()
* test that add_block sets children
* add a test for canonicalize
* extract Pre-digest from header
* utilities for extracting RelayVRFStory from the header-chain
* add approval voting message types
* approval distribution message type
* subsystem skeleton
* state struct
* add futures-timer
* prepare service for babe slot duration
* more skeleton
* better integrate AuxStore
* RelayVRF -> RelayVRFStory
* canonicalize
* implement some tick functionality
* guide: tweaks
* check_approval
* more tweaks and helpers
* guide: add core index to candidate event
* primitives: add core index to candidate event
* runtime: add core index to candidate events
* head handling (session window)
* implement `determine_new_blocks`
* add TODO
* change error type on functions
* compute RelayVRFModulo assignments
* compute RelayVRFDelay assignments
* fix delay tranche calc
* assignment checking
* pluralize
* some dummy code for fetching assignments
* guide: add babe epoch runtime API
* implement a current_epoch() runtime API
* compute assignments
* candidate events get backing group
* import blocks and assignments into DB
* push block approval meta
* add message types, no overseer integration yet
* notify approval distribution of new blocks
* refactor import into separate functions
* impl tranches_to_approve
* guide: improve function signatures
* guide: remove Tick from ApprovalEntry
* trigger and broadcast assignment
* most of approval launching
* remove byteorder crate
* load blocks back to finality, except on startup
* check unchecked assignments
* add claimed core to approval voting message
* fix checks
* assign only to backing group
* remove import_checked_assignment from guide
* newline
* import assignments
* abstract out a bit
* check and import approvals
* check full approvals from assignment import too
* comment
* create a Transaction utility
* must_use
* use transaction in `check_full_approvals`
* wire up wakeups
* add Ord to CandidateHash
* wakeup refactoring
* return candidate info from add_block_entry
* schedule wakeups
* background task: do candidate validation
* forward candidate validation requests
* issue approval votes when requested
* clean up a couple TODOs
* fix up session caching
* clean up last unimplemented!() items
* fix remaining warnings
* remove TODO
* implement handle_approved_ancestor
* update Cargo.lock
* fix runtime API tests
* guide: cleanup assignment checking
* use claimed candidate index instead of core
* extract time to a trait
* tests module
* write a mock clock for testing
* allow swapping out the clock
* make abstract over assignment criteria
* add some skeleton tests and simplify params
* fix backing group check
* do backing group check inside check_assignment_cert
* write some empty test functions to implement
* add a test for non-backing
* test that produced checks pass
* some empty test ideas
* runtime/inclusion: remove outdated TODO
* fix compilation
* av-store: fix tests
* dummy cert
* criteria tests
* move `TestStore` to main tests file
* fix unused warning
* test harness beginnings
* resolve slots renaming fallout
* more compilation fixes
* wip: extract pure data into a separate module
* wip: extract pure data into a separate module
* move types completely to v1
* add persisted_entries
* add conversion trait impls
* clean up some warnings
* extract import logic to own module
* schedule wakeups
* experiment with Actions
* uncomment approval-checking
* separate module for approval checking utilities
* port more code to use actions
* get approval pipeline using actions
* all logic is uncommented
* main loop processes actions
* all loop logic uncommented
* separate function for handling actions
* remove last unimplemented item
* clean up warnings
* State gives read-only access to underlying DB
* tests for approval checking
* tests for approval criteria
* skeleton test module for import
* list of import tests to do
* some test glue code
* test reject bad assignment
* test slot too far in future
* test reject assignment with unknown candidate
* remove loads_blocks tests
* determine_new_blocks back to finalized & harness
* more coverage for determining new blocks
* make `imported_block_info` have less reliance on State
* candidate_info tests
* tests for session caching
* remove println
* extricate DB and main TestStores
* rewrite approval checking logic to counteract early delays
* move state out of function
* update approval-checking tests
* tweak wakeups & scheduling logic
* rename check_full_approvals
* test that assignment import updates candidate
* some approval import tests
* some tests for check_and_apply_approval
* add 'full' qualifier to avoid confusion
* extract should-trigger logic to separate function
* some tests for all triggering
* tests for when we trigger assignments
* test wakeups
* add block utilities for testing
* some more tests for approval updates
* approved_ancestor tests
* new action type for launch approval
* process-wakeup tests
* clean up some warnings
* fix in_future test
* approval checking tests
* tighten up too-far-in-future
* special-case genesis when caching sessions
* fix bitfield len
Co-authored-by: Andronik Ordian <write@reusable.software>
* send our view to new peers immediately
* guide: update
* Fix tests by expecting the view updates
* Add test that we send our view on connection
Co-authored-by: Sergei Shulepov <sergei@parity.io>
* grab guide updates from approval-voting branch
* focus on control flow and behavior, not functions
* add approval voting preamble info
* tabs -> spaces
* skeleton
* skeleton aux-schema module
* start approval types
* start aux schema with aux store
* doc
* finish basic types
* start approval types
* doc
* finish basic types
* write out schema types
* add debug and codec impls to approval types
* add debug and codec impls to approval types
also add some key computation
* add debug and codec impls to approval types
* getters for block and candidate entries
* grumbles
* remove unused AssignmentId
* load_decode utility
* implement DB clearing
* function for adding new block entry to aux store
* start `canonicalize` implementation
* more skeleton
* finish implementing canonicalize
* tag TODO
* implement a test AuxStore
* add allow(unused)
* basic loading and deleting test
* block_entry test function
* add a test for `add_block_entry`
* ensure range is exclusive at end
* test clear()
* test that add_block sets children
* add a test for canonicalize
* Update node/core/approval-voting/src/aux_schema/mod.rs
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* Update node/core/approval-voting/src/aux_schema/tests.rs
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* Update node/core/approval-voting/src/aux_schema/mod.rs
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* scheduler: handle re-scheduling around finalization correctly
* also make sure parathreads get cleaned
* run scheduling in finalization
* Remove stray println!
* Update the schedule call site in inclusion inherent
* Clarify subtlety around SessionStartBlock
* Remove double semi-colon
* reschedule prior to `availability_cores` and in on-initialize
* improve docs
* fix line
* more doc reformat
* remove unneeded call
* avoid unnecessary scheduling on initialize
* split `clear` and `schedule
* Update runtime/parachains/src/scheduler.rs
Co-authored-by: Sergei Shulepov <sergei@parity.io>
Co-authored-by: Sergei Shulepov <sergei@parity.io>
* subsystems have an unbounded channel to the overseer
* Update node/overseer/src/lib.rs
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
* bump Cargo.lock
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
* point to branch
* update babe API implementations
* build
* Revert "point to branch"
This reverts commit 669fde1e58cac1eef1847d5e6b39520fa4953f33.
* update Cargo.lock
* bump
* add candidate hash statement circulation span
* add relay-parent to hash-span
* Some typos and misspellings in docs I found, during my studies. (#2144)
* Fix stale link to overseer docs
* Some typos and mispellings in docs/comments
I found during studying how Polkadot works.
* Rococo V1 (#2141)
* Update to latest master and use 30 minutes sessions
* add bootnodes to chainspec
* Update Substrate
* Update chain-spec
* Update Cargo.lock
* GENESIS
* Change session length to one hour
* Bump spec_version to not fuck anything up ;)
Co-authored-by: Erin Grasmick <erin@parity.io>
* avoid creating duplicate unbacked spans when we see extra statements (#2145)
* improve jaeger spans for statement distribution
* tweak and add failing test for repropagation
* make a change that gets the test passing
* guide: clarify
* remove semicolon
Co-authored-by: Robert Klotzner <eskimor@users.noreply.github.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Co-authored-by: Erin Grasmick <erin@parity.io>
* guide: add candidate information to OccupiedCore
* add descriptor and hash to occupied core type
* guide: add candidate hash to inclusion
* runtime: return candidate info in core state
* bitfield signing: stop querying runtime as much
* minimize going to runtime in availability distribution
* fix availability distribution tests
* guide: remove para ID from Occupied core
* get all crates compiling
* plumbing for rewarding backers
* give validators reward points for participating
* fix tests
* add bitfield rewarding
* add mocks for backing rewards
* add testing for backing & availability rewards
* implement RewardValidators on top of staking
* add to test-runtime and rococo
* add to test-runtime & rococo
* point to source on rewards values
* fix common tests
* do not reward availability anymore
* refactor some functions to not rely on `self`
* factor out common elements of seconding and attesting
* Add Spawn to backing FromJob
* do candidate validation in background
* tests
* address grumbles
* skeleton flow control
* tweaks & rename to approvals distribution
* Update roadmap/implementers-guide/src/node/approval/approval-distribution.md
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* Update roadmap/implementers-guide/src/node/approval/approval-distribution.md
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* add a `NewBlocks` message and dispatch
* new data format for approval distribution
* guide: update view to include finalized block number
* approvals: document view updating
* pruning when peers disconnect
* add remaining message types
* fix link
* network message type
* handle incoming assignments
* import_and_circulate_approval
* handle new blocks
* address review comments
* address review comments and use nifty VRFProof
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* elaborate on runtime API
* clarify what to do if the runtime API calls fail
* Update roadmap/implementers-guide/src/node/approval/approval-voting.md
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* Update roadmap/implementers-guide/src/node/approval/approval-voting.md
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
* fix: ensure candidate validation gets code based on occupied core assumption
* guide: runtime API for historical validation code
* add historical runtime API
* integrate into runtime API subsystem
* remove blocked TODO
* fix service build: enable notifications protocol only under real overseer
* Update node/subsystem/src/messages.rs
Co-authored-by: Sergei Shulepov <sergei@parity.io>
* fix compilation
Co-authored-by: Robert Habermeier <robert@Roberts-MacBook-Pro.local>
Co-authored-by: Sergei Shulepov <sergei@parity.io>
* move validity module to disputes module
* prepare a section on approvals
* extract approval/assignments text to an overview section
* Apply suggestions from code review
Spelling
Co-authored-by: Fedor Sakharov <fedor.sakharov@gmail.com>
* update primitives
* correct parent_head field
* make hrmp field pub
* refactor validation data: runtime
* refactor validation data: messages
* add arguments to full_validation_data runtime API
* port runtime API
* mostly port over candidate validation
* remove some parameters from ValidationParams
* guide: update candidate validation
* update candidate outputs
* update ValidationOutputs in primitives
* port over candidate validation
* add a new test for no-transient behavior
* update util runtime API wrappers
* candidate backing
* fix missing imports
* change some fields of validation data around
* runtime API impl
* update candidate validation
* fix backing tests
* grumbles from review
* fix av-store tests
* fix some more crates
* fix provisioner tests
* fix availability distribution tests
* port collation-generation to new validation data
* fix overseer tests
* Update roadmap/implementers-guide/src/node/utility/candidate-validation.md
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* guide: validation data refactoring
* address grumbles from review
* Update roadmap/implementers-guide/src/types/candidate.md
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
* last comments from review
Co-authored-by: Sergei Shulepov <sergei@parity.io>
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
* update networking types
* port over overseer-protocol message types
* Add the collation protocol to network bridge
* message sending
* stub for ConnectToValidators
* add some helper traits and methods to protocol types
* add collator protocol message
* leaves-updating
* peer connection and disconnection
* add utilities for dispatching multiple events
* implement message handling
* add an observedrole enum with equality and no sentry nodes
* derive partial-eq on network bridge event
* add PartialEq impls for network message types
* add Into implementation for observedrole
* port over existing network bridge tests
* add some more tests
* port bitfield distribution
* port over bitfield distribution tests
* add codec indices
* port PoV distribution
* port over PoV distribution tests
* port over statement distribution
* port over statement distribution tests
* update overseer and service-new
* address review comments
* port availability distribution
* port over availability distribution tests
* Do a small write-up on collation-generation
* preamble to collator protocol
* notes on protocol
* collation-generation: point to collator protocol
* fix missing bracket
* expand on collator protocol wire protocol
* add a couple more sentences
* expand on requests some more
* go higher level
* network bridge: note peerset
* note peer-set = validation for protocols
* add `ConnectToValidators` message
* use ConnectToValidators in collator protocol
* typo
* remove references to sentry nodes
* skeleton for candidate-validation
* add to workspace
* implement candidate validation logic
* guide: note occupied-core assumption for candidate validation
* adjust message doc
* wire together `run` asynchronously
* add a Subsystem implementation
* clean up a couple warnings
* fix compilation errors due to merge
* improve candidate-validation.md
* remove old reference to subsystem-test helpers crate
* update Cargo.lock
* add a couple new Runtime API methods
* add a candidate validation message
* fetch validation data from the chain state
* some tests for assumption checking
* make spawn_validate_exhaustive mockable
* more tests on the error handling side
* fix all other grumbles except for wasm validation API change
* wrap a SpawnNamed in candidate-validation
* warn
* amend guide
* squanch warning
* remove duplicate after merge
* type defaults for ParachainHost
* add ValidationCode message
* implement core loop of runtime API subsystem
* subsystem trait implementation for runtime API subsystem
* implement a mock runtime API
* some tests that ensure requests are forwarded to runtime API correctly
* fix dependency grumbles
* improve RuntimeApiError API
* polkadot-subsystem: update runtime API message types
* update all networking subsystems to use fallible runtime APIs
* fix bitfield-signing and make it use new runtime APIs
* port candidate-backing to handle runtime API errors and new types
* remove old runtime API messages
* remove unused imports
* fix grumbles
* fix backing tests
* rename GlobalValidationSchedule to GlobalValidationData
* guide: update candidate descriptor to contain validation data hash
* guide: add note in inclusion module about checking validation data hash
* primitives: update CandidateDescriptor to contain new hash
* fix payload computation
* add helpers for computing validation data to runtime modules
* guide: note routines
* inclusion: check validation data hash and fix local_validation_data bug
* add a case to candidate_checks and improve that test substantially
* bump versions
* address review comments
* add a test for including code upgrade
* bump kusama version
* bump westend & polkadot versions
* create a README on Runtime APIs
* add ParaId type
* write up runtime APIs
* more preamble
* rename
* rejig runtime APIs
* add occupied_since to `BlockNumber`
* skeleton crate for runtime API subsystem
* improve group_for_core
* improve docs on availability cores runtime API
* guide: freed -> free
* add primitives for runtime APIs
* create a v1 ParachainHost API trait
* guide: make validation code return `Option`al.
* skeleton runtime API helpers
* make parachain-host runtime-generic
* skeleton for most runtime API implementation functions
* guide: add runtime API helper methods
* implement new helpers of the inclusion module
* guide: remove retries check, as it is unneeded
* implement helpers for scheduler module for Runtime APIs
* clean up `validator_groups` implementation
* implement next_rotation_at and last_rotation_at
* guide: more helpers on GroupRotationInfo
* almost finish implementing runtime APIs
* add explicit block parameter to runtime API fns
* guide: generalize number parameter
* guide: add group_responsible to occupied-core
* update primitives due to guide changes
* finishing touches on runtime API implementation; squash warnings
* break out runtime API impl to separate file
* add tests for next_up logic
* test group rotation info
* point to filed TODO
* remove unused TODO [now]
* indentation
* guide: para -> para_id
* rename para field to para_id for core meta
* remove reference to outdated AvailabilityCores type
* add an event in `inclusion` for candidates being included or timing out
* guide: candidate events
* guide: adjust language
* Candidate events type from guide and adjust inclusion event
* implement `candidate_events` runtime API
* fix runtime test compilation
* max -> min
* fix typos
* guide: add `RuntimeAPIRequest::CandidateEvents`
* add assumptions made by the Node-side
* Update roadmap/implementers-guide/src/node/README.md
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* Update roadmap/implementers-guide/src/node/README.md
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
* Update roadmap/implementers-guide/src/node/README.md
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
* more refinements
Co-authored-by: Peter Goodspeed-Niklaus <coriolinus@users.noreply.github.com>
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
* create a v1 primitives module
* Improve guide on availability types
* punctuate
* new parachains runtime uses new primitives
* tests of new runtime now use new primitives
* add ErasureChunk to guide
* export erasure chunk from v1 primitives
* subsystem crate uses v1 primitives
* node-primitives uses new v1 primitives
* port overseer to new primitives
* new-proposer uses v1 primitives (no ParachainHost anymore)
* fix no-std compilation for primitives
* service-new uses v1 primitives
* network-bridge uses new primitives
* statement distribution uses v1 primitives
* PoV distribution uses v1 primitives; add PoV::hash fn
* move parachain to v0
* remove inclusion_inherent module and place into v1
* remove everything from primitives crate root
* remove some unused old types from v0 primitives
* point everything else at primitives::v0
* squanch some warns up
* add RuntimeDebug import to no-std as well
* port over statement-table and validation
* fix final errors in validation and node-primitives
* add dummy Ord impl to committed candidate receipt
* guide: update CandidateValidationMessage
* add primitive for validationoutputs
* expand CandidateValidationMessage further
* bikeshed
* add some impls to omitted-validation-data and available-data
* expand CandidateValidationMessage
* make erasure-coding generic over v1/v0
* update usages of erasure-coding
* implement commitments.hash()
* use Arc<Pov> for CandidateValidation
* improve new erasure-coding method names
* fix up candidate backing
* update docs a bit
* fix most tests and add short-circuiting to make_pov_available
* fix remainder of candidate backing tests
* squanching warns
* squanch it up
* some fallout
* overseer fallout
* free from polkadot-test-service hell
* note that the initializer is responsible for buffering session changes
* amend initializer definition to include session change buffering
* support buffered changes before `on_initialize`
* implement and test session buffering
* Update roadmap/implementors-guide/src/runtime/README.md
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
* expand on how this affects misbehavior reports
* fix typo
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
* introduce candidatedescriptor type
* add PoVDistribution message type
* loosen bound on PoV Distribution to account for equivocations
* re-export some types from the messages module
* begin PoV Distribution subsystem
* remove redundant index from PoV distribution
* define state machine for pov distribution
* handle overseer signals
* set up control flow
* remove `ValidatorStatement` section
* implement PoV fetching
* implement distribution logic
* add missing `
* implement some network bridge event handlers
* stub for message processing, handle our view change
* control flow for handling messages
* handle `awaiting` message
* handle any incoming PoVs and redistribute
* actually provide a subsystem implementation
* remove set-builder notation
* begin testing PoV distribution
* test that we send awaiting messages only to peers with same view
* ensure we distribute awaited PoVs to peers on view changes
* test that peers can complete fetch and are rewarded
* test some reporting logic
* ensure peer is reported for flooding
* test punishing peers diverging from awaited protocol
* test that we eagerly complete peers' awaited PoVs based on what we receive
* test that we prune the awaited set after receiving
* expand pov-distribution in guide to match a change I made
* remove unneeded import
* set up data types and control flow for statement distribution
* add some set-like methods to View
* implement sending to peers
* start fixing equivocation handling
* Add a section to the statement distribution subsystem on equivocations and flood protection
* fix typo and amend wording
* implement flood protection
* have peer knowledge tracker follow when peer first learns about a candidate
* send dependents after circulating
* add another TODO
* trigger send in one more place
* refactors from review
* send new statements to candidate backing
* instantiate active head data with runtime API values
* track our view changes and peer view changes
* apply a benefit to peers who send us statements we want
* remove unneeded TODO
* add some comments and improve Hash implementation
* start tests and fix `note_statement`
* test active_head seconding logic
* test that the per-peer tracking logic works
* test per-peer knowledge tracker
* test that peer view updates lead to messages being sent
* test statement circulation
* address review comments
* have view set methods return references
