in src/datasource.ts [498:509]
private fetchGrafanaBackend(method: string, postfix: string, body?: any): Observable<FetchResponse> {
const request: BackendSrvRequest = {
url: this.getGrafanaUrl(postfix),
method,
headers: HEADERS,
};
if (body != null) {
request.data = body;
}
return from(getBackendSrv().fetch(request));
}