public constructor(
		private _rootProcessId: number,
		private _terminalInstance: ITerminalInstance,
		private _xterm: XTermTerminal
	) {
		if (!platform.isWindows) {
			throw new Error(`WindowsShellHelper cannot be instantiated on ${platform.platform}`);
		}

		if (!windowsProcessTree) {
			windowsProcessTree = require.__$__nodeRequire('windows-process-tree');
		}

		this._isDisposed = false;
		this._onCheckShell = new Emitter<TPromise<string>>();
		// The debounce is necessary to prevent multiple processes from spawning when
		// the enter key or output is spammed
		debounceEvent(this._onCheckShell.event, (l, e) => e, 150, true)(() => {
			setTimeout(() => {
				this.checkShell();
			}, 50);
		});

		// We want to fire a new check for the shell on a linefeed, but only
		// when parsing has finished which is indicated by the cursormove event.
		// If this is done on every linefeed, parsing ends up taking
		// significantly longer due to resetting timers. Note that this is
		// private API.
		this._xterm.on('linefeed', () => this._newLineFeed = true);
		this._xterm.on('cursormove', () => {
			if (this._newLineFeed) {
				this._onCheckShell.fire();
			}
		});

		// Fire a new check for the shell when any key is pressed.
		this._xterm.on('keypress', () => this._onCheckShell.fire());
	}

		(import('windows-process-tree')).then(mod => {
			if (this._isDisposed) {
				return;
			}

			windowsProcessTree = mod;
			this._onCheckShell = new Emitter<TPromise<string>>();
			// The debounce is necessary to prevent multiple processes from spawning when
			// the enter key or output is spammed
			debounceEvent(this._onCheckShell.event, (l, e) => e, 150, true)(() => {
				setTimeout(() => {
					this.checkShell();
				}, 50);
			});

			// We want to fire a new check for the shell on a linefeed, but only
			// when parsing has finished which is indicated by the cursormove event.
			// If this is done on every linefeed, parsing ends up taking
			// significantly longer due to resetting timers. Note that this is
			// private API.
			this._xterm.on('linefeed', () => this._newLineFeed = true);
			this._xterm.on('cursormove', () => {
				if (this._newLineFeed) {
					this._onCheckShell.fire();
				}
			});

			// Fire a new check for the shell when any key is pressed.
			this._xterm.on('keypress', () => this._onCheckShell.fire());
		});