src/vs/workbench/contrib/terminal/browser/terminalProcessManager.ts/AckDataBufferer/ack
class AckDataBufferer:	ack(charCount: number) {
		this._unsentCharCount += charCount;
		while (this._unsentCharCount > FlowControlConstants.CharCountAckSize) {
			this._unsentCharCount -= FlowControlConstants.CharCountAckSize;
			this._callback(FlowControlConstants.CharCountAckSize);
		}
	}