/// <summary>
 /// GET /v1/calls - retrieve information about all your Calls
 /// <param name="filter">Filter to search calls on</param>
 /// <param name="creds">(Optional) Overridden credentials for only this request</param>
 /// </summary>
 /// <exception cref="VonageHttpRequestException">thrown if an error is encountered when talking to the API</exception>
 public Task <PageResponse <CallList> > GetCallsAsync(CallSearchFilter filter, Credentials creds = null)
 {
     return(ApiRequest.DoGetRequestWithQueryParametersAsync <PageResponse <CallList> >(
                ApiRequest.GetBaseUri(ApiRequest.UriType.Api, CALLS_ENDPOINT),
                ApiRequest.AuthType.Bearer,
                filter,
                creds ?? Credentials
                ));
 }
 public PageResponse <CallList> GetCalls(CallSearchFilter filter, Credentials creds = null)
 {
     return(GetCallsAsync(filter, creds).GetAwaiter().GetResult());
 }