code: public Observable<ServiceResponse<HybridConnectionKeyInner>> listHybridConnectionKeysWithServiceResponseAsync(String resourceGroupName, String name, String namespaceName, String relayName) {
          if (resourceGroupName == null) {
              throw new IllegalArgumentException("Parameter resourceGroupName is required and cannot be null.");
          }
          if (name == null) {
              throw new IllegalArgumentException("Parameter name is required and cannot be null.");
          }
          if (namespaceName == null) {
              throw new IllegalArgumentException("Parameter namespaceName is required and cannot be null.");
          }
          if (relayName == null) {
              throw new IllegalArgumentException("Parameter relayName is required and cannot be null.");
          }
          if (this.client.subscriptionId() == null) {
              throw new IllegalArgumentException("Parameter this.client.subscriptionId() is required and cannot be null.");
          }
          if (this.client.apiVersion() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiVersion() is required and cannot be null.");
          }
          return service.listHybridConnectionKeys(resourceGroupName, name, namespaceName, relayName, this.client.subscriptionId(), this.client.apiVersion(), this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<HybridConnectionKeyInner>>>() {
                  @Override
                  public Observable<ServiceResponse<HybridConnectionKeyInner>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<HybridConnectionKeyInner> clientResponse = listHybridConnectionKeysDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Get the send key name and value of a Hybrid Connection.
  Get the send key name and value of a Hybrid Connection.
  
  @param resourceGroupName Name of the resource group to which the resource belongs.
  @param name Name of the App Service plan.
  @param namespaceName The name of the Service Bus namespace.
  @param relayName The name of the Service Bus relay.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the HybridConnectionKeyInner object