code: func UnmarshalDefinition(b []byte) (*messages.TriggeringPolicy, error) {
  	msg := &messages.TriggeringPolicy{}
  	if len(b) != 0 {
  		if err := proto.Unmarshal(b, msg); err != nil {
  			return nil, errors.Annotate(err, "failed to unmarshal TriggeringPolicy").Err()
  		}
  	}
  	if msg.Kind == 0 {
  		msg.Kind = defaultPolicy.Kind
  	}
  	if msg.MaxConcurrentInvocations == 0 {
  		msg.MaxConcurrentInvocations = defaultPolicy.MaxConcurrentInvocations
  	}
  	if msg.MaxBatchSize == 0 {
  		msg.MaxBatchSize = defaultPolicy.MaxBatchSize
  	}
  	return msg, nil
  }
docs: // UnmarshalDefinition deserializes TriggeringPolicy, filling in defaults.