remove Database::flush

src/database/any.rs

@@ -255,10 +255,6 @@ 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

@@ -158,13 +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>;
-
-    #[deprecated(
-        since = "0.18.0",
-        note = "The flush function is only needed for the sled database on mobile, instead for mobile use the sqlite database."
-    )]
-    /// 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

@@ -891,10 +891,6 @@ impl Database for SqliteDatabase {
             }
         }
     }
-
-    fn flush(&mut self) -> Result<(), Error> {
-        Ok(())
-    }
 }
 
 impl BatchDatabase for SqliteDatabase {