code: function addWalkEntriesMethod(ZipFile, Promise) {
  	ZipFile.prototype.walkEntries = function(callback, numEntries) {
  		callback = wrapFunctionToReturnPromise(callback, Promise);
  
  		return new Promise((resolve, reject) => {
  			walkNextEntry(this, callback, numEntries, 0, err => {
  				if (err) return reject(err);
  				resolve();
  			});
  		});
  	};
  }
docs: /*
  Walk all ZipFile entries
  Walks through each entry and calls `fn` with each.
  Returns a promise which resolves when all have been read.