Second pass over Address type and start impl in Subxt

core/src/utils/mod.rs

@@ -73,8 +73,12 @@ unsafe impl<T> Sync for PhantomDataSendSync<T> {}
 /// as `BTreeMap` which allows us to easily swap the two during codegen.
 pub type KeyedVec<K, V> = Vec<(K, V)>;
 
-/// A unit marker struct.
-pub struct Yes;
+/// A unit marker enum.
+pub enum Yes {}
+/// A unit marker enum.
+pub enum Maybe {}
+/// A unit marker enum.
+pub enum No {}
 
 /// A quick helper to encode some bytes to hex.
 pub fn to_hex(bytes: impl AsRef<[u8]>) -> String {