Fast Unstake Pallet (#12129)

* add failing test for itamar

* an ugly example of fast unstake

* Revert "add failing test for itamar"

This reverts commit 16c4d8015698a0684c090c54fce8b470a2d2feb2.

* fast unstake wip

* clean it up a bit

* some comments

* on_idle logic

* fix

* comment

* new working version, checks all pass, looking good

* some notes

* add mock boilerplate

* more boilerplate

* simplify the weight stuff

* ExtBuilder for pools

* fmt

* rm bags-list, simplify setup_works

* mock + tests boilerplate

* make some benchmarks work

* mock boilerplate

* tests boilerplate

* run_to_block works

* add Error enums

* add test

* note

* make UnstakeRequest fields pub

* some tests

* fix origin

* fmt

* add fast_unstake_events_since_last_call

* text

* rewrite some benchmes and fix them -- the outcome is still strange

* Fix weights

* cleanup

* Update frame/election-provider-support/solution-type/src/single_page.rs

* fix build

* Fix pools tests

* iterate teset + mock

* test unfinished

* cleanup and add some tests

* add test successful_multi_queue

* comment

* rm Head check

* add TODO

* complete successful_multi_queue

* + test early_exit

* fix a lot of things above the beautiful atlantic ocean 🌊

* seemingly it is finished now

* Fix build

* ".git/.scripts/fmt.sh" 1

* Fix slashing amount as well

* better docs

* abstract types

* rm use

* import

* Update frame/nomination-pools/benchmarking/src/lib.rs

Co-authored-by: Nitwit <47109040+nitwit69@users.noreply.github.com>

* Update frame/fast-unstake/src/types.rs

Co-authored-by: Nitwit <47109040+nitwit69@users.noreply.github.com>

* Fix build

* fmt

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>

* make bounded

* feedback from code review with Ankan

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/lib.rs

Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

* Update frame/fast-unstake/src/mock.rs

* update to master

* some final review comments

* fmt

* fix clippy

* remove unused

* ".git/.scripts/fmt.sh" 1

* make it all build again

* fmt

* undo fishy change

Co-authored-by: Ross Bulat <ross@jkrbinvestments.com>
Co-authored-by: command-bot <>
Co-authored-by: Nitwit <47109040+nitwit69@users.noreply.github.com>
Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
Co-authored-by: Roman Useinov <roman.useinov@gmail.com>

substrate/frame/election-provider-support/src/lib.rs

@@ -136,7 +136,7 @@
 //!         type BlockNumber = BlockNumber;
 //!         type Error = &'static str;
 //!         type DataProvider = T::DataProvider;
-//!
+//! 	        fn ongoing() -> bool { false }
 //!         fn elect() -> Result<Supports<AccountId>, Self::Error> {
 //!             Self::DataProvider::electable_targets(None)
 //!                 .map_err(|_| "failed to elect")
@@ -370,6 +370,9 @@ pub trait ElectionProvider {
 		BlockNumber = Self::BlockNumber,
 	>;
 
+	/// Indicate if this election provider is currently ongoing an asynchronous election or not.
+	fn ongoing() -> bool;
+
 	/// Elect a new set of winners, without specifying any bounds on the amount of data fetched from
 	/// [`Self::DataProvider`]. An implementation could nonetheless impose its own custom limits.
 	///
@@ -420,6 +423,10 @@ where
 	fn elect() -> Result<Supports<AccountId>, Self::Error> {
 		Err("<NoElection as ElectionProvider> cannot do anything.")
 	}
+
+	fn ongoing() -> bool {
+		false
+	}
 }
 
 /// A utility trait for something to implement `ElectionDataProvider` in a sensible way.