code: public Observable<AssemblyDefinitionInner> createOrUpdateAsync(String resourceGroupName, String integrationAccountName, String assemblyArtifactName, AssemblyDefinitionInner assemblyArtifact) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, integrationAccountName, assemblyArtifactName, assemblyArtifact).map(new Func1<ServiceResponse<AssemblyDefinitionInner>, AssemblyDefinitionInner>() {
              @Override
              public AssemblyDefinitionInner call(ServiceResponse<AssemblyDefinitionInner> response) {
                  return response.body();
              }
          });
      }
docs: Create or update an assembly for an integration account.
  
  @param resourceGroupName The resource group name.
  @param integrationAccountName The integration account name.
  @param assemblyArtifactName The assembly artifact name.
  @param assemblyArtifact The assembly artifact.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the AssemblyDefinitionInner object