code: func (h *handler) runMethod(ctx context.Context, msg *jsonrpcMessage, callb *callback, args []reflect.Value) *jsonrpcMessage {
  	result, err := callb.call(ctx, msg.Method, args)
  	if err != nil {
  		return msg.errorResponse(err)
  	}
  	return msg.response(result)
  }
docs: // runMethod runs the Go callback for an RPC method.