How to use the vscode-languageserver-protocol.Emitter function in vscode-languageserver-protocol

constructor() {
        this._documents = Object.create(null);
        this._onDidChangeContent = new vscode_languageserver_protocol_1.Emitter();
        this._onDidOpen = new vscode_languageserver_protocol_1.Emitter();
        this._onDidClose = new vscode_languageserver_protocol_1.Emitter();
        this._onDidSave = new vscode_languageserver_protocol_1.Emitter();
        this._onWillSave = new vscode_languageserver_protocol_1.Emitter();
    }
    /**

public registLanguageClient(client: LanguageClient): Disposable {
    let disposables: Disposable[] = []
    let onDidServiceReady = new Emitter()

    let service: IServiceProvider = {
      client,
      id: client.id,
      name: client.name,
      selector: client.clientOptions.documentSelector,
      state: ServiceStat.Initial,
      onServiceReady: onDidServiceReady.event,
      start: (): Promise => {
        if (service.state != ServiceStat.Initial && service.state != ServiceStat.Stopped) {
          return Promise.resolve()
        }
        if (client.getPublicState() == State.Starting) {
          return Promise.resolve()
        }
        service.state = ServiceStat.Starting

constructor() {
        this._documents = Object.create(null);
        this._onDidChangeContent = new vscode_languageserver_protocol_1.Emitter();
        this._onDidOpen = new vscode_languageserver_protocol_1.Emitter();
        this._onDidClose = new vscode_languageserver_protocol_1.Emitter();
        this._onDidSave = new vscode_languageserver_protocol_1.Emitter();
        this._onWillSave = new vscode_languageserver_protocol_1.Emitter();
    }
    /**

constructor() {
        this._documents = Object.create(null);
        this._onDidChangeContent = new vscode_languageserver_protocol_1.Emitter();
        this._onDidOpen = new vscode_languageserver_protocol_1.Emitter();
        this._onDidClose = new vscode_languageserver_protocol_1.Emitter();
        this._onDidSave = new vscode_languageserver_protocol_1.Emitter();
        this._onWillSave = new vscode_languageserver_protocol_1.Emitter();
    }
    /**

public initialize(capabilities: ClientCapabilities): void {
			let workspaceCapabilities = capabilities.workspace;
			if (workspaceCapabilities && workspaceCapabilities.workspaceFolders) {
				this._onDidChangeWorkspaceFolders = new Emitter();
				this.connection.onNotification(DidChangeWorkspaceFoldersNotification.type, (params) => {
					this._onDidChangeWorkspaceFolders.fire(params.event);
				});
			}
		}
		getWorkspaceFolders(): Promise {

constructor() {
        this._documents = Object.create(null);
        this._onDidChangeContent = new vscode_languageserver_protocol_1.Emitter();
        this._onDidOpen = new vscode_languageserver_protocol_1.Emitter();
        this._onDidClose = new vscode_languageserver_protocol_1.Emitter();
        this._onDidSave = new vscode_languageserver_protocol_1.Emitter();
        this._onWillSave = new vscode_languageserver_protocol_1.Emitter();
    }
    /**

constructor() {
        this._documents = Object.create(null);
        this._onDidChangeContent = new vscode_languageserver_protocol_1.Emitter();
        this._onDidOpen = new vscode_languageserver_protocol_1.Emitter();
        this._onDidClose = new vscode_languageserver_protocol_1.Emitter();
        this._onDidSave = new vscode_languageserver_protocol_1.Emitter();
        this._onWillSave = new vscode_languageserver_protocol_1.Emitter();
    }
    /**