Encode request into client_message

def encode_request(name, replica_timestamps, target_replica):
    """ Encode request into client_message"""
    client_message = ClientMessage(payload_size=calculate_size(name, replica_timestamps, target_replica))
    client_message.set_message_type(REQUEST_TYPE)
    client_message.set_retryable(RETRYABLE)
    client_message.append_str(name)
    client_message.append_int(len(replica_timestamps))
    for replica_timestamps_item in replica_timestamps:
        key = replica_timestamps_item[0]
        val = replica_timestamps_item[1]
        client_message.append_str(key)
        client_message.append_long(val)

    AddressCodec.encode(client_message, target_replica)
    client_message.update_frame_length()
    return client_message