src/vs/editor/browser/widget/diffEditorWidget.ts/DiffEditorWidget/_setState
class DiffEditorWidget:	private _setState(newState: editorBrowser.DiffEditorState): void {
		if (this._state === newState) {
			return;
		}
		this._state = newState;

		if (this._updatingDiffProgress) {
			this._updatingDiffProgress.done();
			this._updatingDiffProgress = null;
		}

		if (this._state === editorBrowser.DiffEditorState.ComputingDiff) {
			this._updatingDiffProgress = this._editorProgressService.show(true, 1000);
		}
	}