src/vs/workbench/api/browser/mainThreadOutputService.ts/MainThreadOutputService/$update
class MainThreadOutputService:	public async $update(channelId: string, mode: OutputChannelUpdateMode, till?: number): Promise<void> {
		const channel = this._getChannel(channelId);
		if (channel) {
			if (mode === OutputChannelUpdateMode.Append) {
				channel.update(mode);
			} else if (isNumber(till)) {
				channel.update(mode, till);
			}
		}
	}