Is this how we should do it man?

```
					let iStream = Cc["@mozilla.org/io/arraybuffer-input-stream;1"]
						.createInstance(Ci.nsIArrayBufferInputStream);

					iStream.setData(data,0,data.byteLength);
							zipWriter.addEntryStream(n, e.lastModifiedTime,
								Ci.nsIZipWriter.COMPRESSION_FASTEST,
								zipReader.getInputStream(iStream), !1);

					let nFile = FileUtils.getFile("TmpD", [Math.random()])
						oStream = FileUtils.openSafeFileOutputStream(nFile);
```

Data in our case is the `this.ownerDocument.querySelector('#blob_contents').value` but how to feed that into `data` so I can get `data.byteLength`?