src/vs/workbench/api/common/extHostTextEditor.ts/ExtHostTextEditor/_runOnProxy
class ExtHostTextEditor:	private _runOnProxy(callback: () => Promise<any>): Promise<ExtHostTextEditor | undefined | null> {
		if (this._disposed) {
			this._logService.warn('TextEditor is closed/disposed');
			return Promise.resolve(undefined);
		}

		return callback().then(() => this, err => {
			if (!(err instanceof Error && err.name === 'DISPOSED')) {
				this._logService.warn(err);
			}
			return null;
		});
	}