function onGlobEnd() {
    this._pending--;
    this._maybeFinalize();
  }
Appends a directory and its files, recursively, given its dirpath.

@param  {String} dirpath The source directory path.
@param  {String} destpath The destination path within the archive.
@param  {(EntryData|Function)} data See also [ZipEntryData]{@link ZipEntryData} and
[TarEntryData]{@link TarEntryData}.
@return {this}