code: func (fw *JSONRPC) getRequestBody(action string, info map[string]string, timeout int) ([]byte, error) {
  	args := &JSONRPC_Args{
  		User:    info["username"],
  		MAC:     info["mac"],
  		IP:      info["ip"],
  		Role:    info["role"],
  		Timeout: timeout,
  	}
  	body, err := json2.EncodeClientRequest(action, args)
  	return body, err
  }
docs: // Create JSON-RPC request body