default void sendForProtocol(final String protocol, final MessageData message)
      throws PeerNotConnected {
    send(capability(protocol), message);
  }
Sends a message to the peer for the given subprotocol

@param protocol the subprotocol name
@param message the message to send
@throws PeerNotConnected if the peer has disconnected
ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/rlpx/connections/PeerConnection.java