return null
      } else if (methodName == "protocols" && callArgs.isEmpty()) {
        return protocols // Client advertises these protocols.
      } else if ((methodName == "selectProtocol" || methodName == "select") &&
        String::class.java == returnType &&
        callArgs.size == 1 &&
        callArgs[0] is List<*>
      ) {
        val peerProtocols = callArgs[0] as List<*>