extensions/git/src/model.ts/Model/registerRemoteSourcePublisher
class Model:	registerRemoteSourcePublisher(publisher: RemoteSourcePublisher): Disposable {
		this.remoteSourcePublishers.add(publisher);
		this._onDidAddRemoteSourcePublisher.fire(publisher);

		return toDisposable(() => {
			this.remoteSourcePublishers.delete(publisher);
			this._onDidRemoveRemoteSourcePublisher.fire(publisher);
		});
	}