code: public Observable<PacketCaptureResultInner> createAsync(String resourceGroupName, String networkWatcherName, String packetCaptureName, PacketCaptureInner parameters) {
          return createWithServiceResponseAsync(resourceGroupName, networkWatcherName, packetCaptureName, parameters).map(new Func1<ServiceResponse<PacketCaptureResultInner>, PacketCaptureResultInner>() {
              @Override
              public PacketCaptureResultInner call(ServiceResponse<PacketCaptureResultInner> response) {
                  return response.body();
              }
          });
      }
docs: Create and start a packet capture on the specified VM.
  
  @param resourceGroupName The name of the resource group.
  @param networkWatcherName The name of the network watcher.
  @param packetCaptureName The name of the packet capture session.
  @param parameters Parameters that define the create packet capture operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request