code: func validateIAMRoleCredentialsMessage(message *ecsacs.IAMRoleCredentialsMessage) error {
  	if message == nil {
  		return fmt.Errorf("empty credentials message")
  	}
  
  	messageId := aws.StringValue(message.MessageId)
  	if messageId == "" {
  		return fmt.Errorf("message id not set in credentials message")
  	}
  
  	if aws.StringValue(message.TaskArn) == "" {
  		return fmt.Errorf("task Arn not set in credentials message")
  	}
  
  	if message.RoleCredentials == nil {
  		return fmt.Errorf("role Credentials not set in credentials message: messageId: %s", messageId)
  	}
  
  	if aws.StringValue(message.RoleCredentials.CredentialsId) == "" {
  		return fmt.Errorf("role Credentials ID not set in credentials message: messageId: %s", messageId)
  	}
  
  	return nil
  }
docs: // validateIAMRoleCredentialsMessage validates fields in the IAMRoleCredentialsMessage
  // It returns an error if any of the following fields are not set in the message:
  // messageId, taskArn, roleCredentials