code: func (d *serverDescription) resolveInputMessage(service, method string) (*descriptor.DescriptorProto, error) {
  	_, obj, _ := descutil.Resolve(d.Description, service)
  	serviceDesc, ok := obj.(*descriptor.ServiceDescriptorProto)
  	if !ok {
  		return nil, fmt.Errorf("service %q not found", service)
  	}
  
  	mi := descutil.FindMethodForService(serviceDesc, method)
  	if mi == -1 {
  		return nil, fmt.Errorf("method %q in service %q not found", method, service)
  	}
  
  	msgName := serviceDesc.Method[mi].GetInputType()
  	msgName = strings.TrimPrefix(msgName, ".")
  	return d.resolveMessage(msgName)
  }
docs: // resolveInputMessage resolves input message type of a method.