remove Database::flush

Author: kafaichoi

CHANGELOG.md

@@ -25,6 +25,8 @@ To decouple the `Wallet` from the `Blockchain` we've made major changes:
 - Stop making a request for the block height when calling `Wallet:new`.
 - Added `SyncOptions` to capture extra (future) arguments to `Wallet::sync`.
 - Removed `max_addresses` sync parameter which determined how many addresses to cache before syncing since this can just be done with `ensure_addresses_cached`.
+- remove `flush` method from the `Database` trait.
+
 
 ## [v0.16.1] - [v0.16.0]
 
@@ -437,4 +439,4 @@ final transaction is created by calling `finish` on the builder.
 [v0.16.0]: https://github.com/bitcoindevkit/bdk/compare/v0.15.0...v0.16.0
 [v0.16.1]: https://github.com/bitcoindevkit/bdk/compare/v0.16.0...v0.16.1
 [v0.17.0]: https://github.com/bitcoindevkit/bdk/compare/v0.16.1...v0.17.0
-[unreleased]: https://github.com/bitcoindevkit/bdk/compare/v0.17.0...HEAD
+[unreleased]: https://github.com/bitcoindevkit/bdk/compare/v0.17.0...HEAD

src/database/any.rs

@@ -254,10 +254,6 @@ impl Database for AnyDatabase {
     fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error> {
         impl_inner_method!(AnyDatabase, self, increment_last_index, keychain)
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        impl_inner_method!(AnyDatabase, self, flush)
-    }
 }
 
 impl BatchOperations for AnyBatch {

src/database/keyvalue.rs

@@ -402,10 +402,6 @@ impl Database for Tree {
             Ok(val)
         })
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(Tree::flush(self).map(|_| ())?)
-    }
 }
 
 impl BatchDatabase for Tree {

src/database/memory.rs

@@ -449,10 +449,6 @@ impl Database for MemoryDatabase {
 
         Ok(*value)
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(())
-    }
 }
 
 impl BatchDatabase for MemoryDatabase {

src/database/mod.rs

@@ -158,9 +158,6 @@ pub trait Database: BatchOperations {
     ///
     /// It should insert and return `0` if not present in the database
     fn increment_last_index(&mut self, keychain: KeychainKind) -> Result<u32, Error>;
-
-    /// Force changes to be written to disk
-    fn flush(&mut self) -> Result<(), Error>;
 }
 
 /// Trait for a database that supports batch operations

src/database/sqlite.rs

@@ -881,10 +881,6 @@ impl Database for SqliteDatabase {
             }
         }
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(())
-    }
 }
 
 impl BatchDatabase for SqliteDatabase {