src/vs/base/parts/ipc/node/ipc.net.ts/ZlibDeflateStream/flush
class ZlibDeflateStream:	public flush(callback: (data: VSBuffer) => void): void {
		// See https://zlib.net/manual.html#Constants
		this._zlibDeflate.flush(/*Z_SYNC_FLUSH*/2, () => {
			this._tracer.traceSocketEvent(SocketDiagnosticsEventType.zlibDeflateFlushFired);

			let data = VSBuffer.concat(this._pendingDeflateData);
			this._pendingDeflateData.length = 0;

			// See https://tools.ietf.org/html/rfc7692#section-7.2.1
			data = data.slice(0, data.byteLength - 4);

			callback(data);
		});
	}