feat!: rm persist submodule

Remove `PersistBackend`, `PersistBackendAsync`, `StageExt` and
`StageExtAsync`. Remove `async` feature flag and dependency. Update
examples and wallet.

crates/file_store/README.md

@@ -1,6 +1,6 @@
 # BDK File Store
 
-This is a simple append-only flat file implementation of [`PersistBackend`](bdk_chain::persist::PersistBackend).
+This is a simple append-only flat file database for persisting [`bdk_chain`] changesets.
 
 The main structure is [`Store`] which works with any [`bdk_chain`] based changesets to persist data into a flat file.
 

crates/file_store/src/store.rs

@@ -1,5 +1,4 @@
 use crate::{bincode_options, EntryIter, FileError, IterError};
-use bdk_chain::persist::PersistBackend;
 use bdk_chain::Append;
 use bincode::Options;
 use std::{
@@ -21,27 +20,6 @@ where
     marker: PhantomData<C>,
 }
 
-impl<C> PersistBackend<C> for Store<C>
-where
-    C: Append
-        + Debug
-        + serde::Serialize
-        + serde::de::DeserializeOwned
-        + core::marker::Send
-        + core::marker::Sync,
-{
-    type WriteError = io::Error;
-    type LoadError = AggregateChangesetsError<C>;
-
-    fn write_changes(&mut self, changeset: &C) -> Result<(), Self::WriteError> {
-        self.append_changeset(changeset)
-    }
-
-    fn load_changes(&mut self) -> Result<Option<C>, Self::LoadError> {
-        self.aggregate_changesets()
-    }
-}
-
 impl<C> Store<C>
 where
     C: Append
@@ -448,7 +426,7 @@ mod test {
                     acc
                 });
             // We write after a short read.
-            db.write_changes(&last_changeset)
+            db.append_changeset(&last_changeset)
                 .expect("last write must succeed");
             Append::append(&mut exp_aggregation, last_changeset.clone());
             drop(db);