BigtableAsyncBufferedMutator implements AsyncBufferedMutator { @Override public void flush() { helper.sendUnsent(); } BigtableAsyncBufferedMutator(
      BigtableApi bigtableApi, BigtableHBaseSettings settings, HBaseRequestAdapter adapter); @Override void close(); @Override void flush(); @Override Configuration getConfiguration(); @Override TableName getName(); @Override long getWriteBufferSize(); @Override List<CompletableFuture<Void>> mutate(List<? extends Mutation> mutations); @Override CompletableFuture<Void> mutate(final Mutation mutation);  }
@Test public void testFlush() { doNothing().when(mockBulkMutation).sendUnsent(); asyncBufferedMutator.flush(); verify(mockBulkMutation).sendUnsent(); }