extensions/typescript-language-features/src/tsServer/bufferSyncSupport.ts/BufferSyncSupport/interruptGetErr
class BufferSyncSupport:	public interruptGetErr<R>(f: () => R): R {
		if (!this.pendingGetErr
			|| this.client.configuration.enableProjectDiagnostics // `geterr` happens on separate server so no need to cancel it.
		) {
			return f();
		}

		this.pendingGetErr.cancel();
		this.pendingGetErr = undefined;
		const result = f();
		this.triggerDiagnostics();
		return result;
	}