public void Put(byte[] key, byte[] value)
 {
     Native.leveldb_writebatch_put(handle, key, (UIntPtr)key.Length, value, (UIntPtr)value.Length);
 }
 public void Put(Slice key, Slice value)
 {
     Native.leveldb_writebatch_put(handle, key.buffer, (UIntPtr)key.buffer.Length, value.buffer, (UIntPtr)value.buffer.Length);
 }