public String getStoreCheckpointDir(File taskStoreDir, CheckpointId checkpointId) {
    return taskStoreDir.getPath() + "-" + checkpointId.serialize();
  }
Returns the path for a storage engine to create its checkpoint based on the current checkpoint id.

@param taskStoreDir directory of the store as returned by {@link #getTaskStoreDir}
@param checkpointId current checkpoint id
@return String denoting the file path of the store with the given checkpoint id
samza-core/src/main/java/org/apache/samza/storage/StorageManagerUtil.java