const requestHeaders: Headers = new Headers();
		requestHeaders.append('Authorization', 'Bearer <your token in step 1>');

		const opt: IHttpClientOptions = {
			headers: requestHeaders
		};
		var url = `https://api.yammer.com/api/v1/messages.json`;
		this.props.context.httpClient.get(url, HttpClient.configurations.v1, opt)
			.then((res: HttpClientResponse): Promise<any> => {
				if (res.status == 200) {
					return res.json();
				} else {
					return null;
				}
			})
			.then((data: any): void => {
				console.log(data);
				this.items = [];
				for (let message of data.messages) {
					this.items.push(
						<div className="row">
							<div className="col-12">
								{message.id}
								<br />
								{message.body.plain}
								<hr />
							</div>
						</div>
					);
				}
				this.forceUpdate();
			});