code: func (p *Peer) getProto(code uint64) (*protoRW, error) {
  	for _, proto := range p.running {
  		if code >= proto.offset && code < proto.offset+proto.Length {
  			return proto, nil
  		}
  	}
  	return nil, newPeerError(errInvalidMsgCode, "%d", code)
  }
docs: // getProto finds the protocol responsible for handling
  // the given message code.