func (rpc *AergoRPCService) ListBlockMetadataStream(in *types.Empty, stream types.AergoRPCService_ListBlockMetadataStreamServer) error {
    streamID := atomic.AddUint32(&rpc.streamID, 1)
    rpc.blockMetadataStreamLock.Lock()
    metadataStream := NewListBlockMetaStream(streamID, stream)
    rpc.blockMetadataStream[streamID] = metadataStream