code: public Observable<ConnectionSharedKeyInner> getSharedKeyAsync(String resourceGroupName, String virtualNetworkGatewayConnectionName) {
          return getSharedKeyWithServiceResponseAsync(resourceGroupName, virtualNetworkGatewayConnectionName).map(new Func1<ServiceResponse<ConnectionSharedKeyInner>, ConnectionSharedKeyInner>() {
              @Override
              public ConnectionSharedKeyInner call(ServiceResponse<ConnectionSharedKeyInner> response) {
                  return response.body();
              }
          });
      }
docs: The Get VirtualNetworkGatewayConnectionSharedKey operation retrieves information about the specified virtual network gateway connection shared key through Network resource provider.
  
  @param resourceGroupName The name of the resource group.
  @param virtualNetworkGatewayConnectionName The virtual network gateway connection shared key name.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the ConnectionSharedKeyInner object