nsIDownloader
A downloader is a special implementation of a nsIStreamListener that will
make the contents of the stream available as a file. This may utilize the
disk cache as an optimization to avoid an extra copy of the data on disk.
The resulting file is valid from the time the downloader completes until
the last reference to the downloader is released.
Initialize this downloader
| observer | the observer to be notified when the download completes. |
| downloadLocation | the location where the stream contents should be written. if null, the downloader will select a location and the resulting file will be deleted (or otherwise made invalid) when the downloader object is destroyed. if an explicit download location is specified then the resulting file will not be deleted, and it will be the callers responsibility to keep track of the file, etc. |