@Override
  public String toString() {
    return "writer=" + (path != null ? path.toString() : null) + ", name=" + name + ", compression="
      + hFileContext.getCompression().getName();
  }
Returns Path or null if we were passed a stream rather than a Path.
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFileWriterImpl.java