@Override
  public String toString() {
    final StringBuilder sb = new StringBuilder("ContainerPlacementRequestMessage{");
    sb.append(" UUID: ").append(uuid);
    sb.append(", Processor ID: ").append(processorId);
    sb.append(", deploymentId='").append(deploymentId).append('\'');
    sb.append(", destinationHost='").append(destinationHost).append('\'');
    sb.append(", requestExpiry=").append(requestExpiry);
    sb.append(", statusCode=").append(statusCode);
    sb.append(", timestamp=").append(timestamp);
    sb.append('}');
    return sb.toString();
  }
Encapsulates the request sent from the external controller to the JobCoordinator to take a container placement action
samza-api/src/main/java/org/apache/samza/container/placement/ContainerPlacementRequestMessage.java