public int getPartitionCount() {
    if (partitionCount > 0) {
      return partitionCount;
    }
    return new JobConfig(getConfig()).getContainerCount();
  }
Getter for the number of partitions to create on a new StreamAppender stream. See also {@link #activateOptions()} for when this is called.
Example: {@literal <param name="PartitionCount" value="4"/>}
This needs to be called after the full Samza job config is available in {@link LoggingContextHolder}.
@return The configured partition count of the StreamAppender stream. If not set, returns {@link JobConfig#getContainerCount()}.
samza-log4j/src/main/java/org/apache/samza/logging/log4j/StreamAppender.java