code: public Observable<ServiceTierAdvisorInner> getAsync(String resourceGroupName, String serverName, String databaseName, String serviceTierAdvisorName) {
          return getWithServiceResponseAsync(resourceGroupName, serverName, databaseName, serviceTierAdvisorName).map(new Func1<ServiceResponse<ServiceTierAdvisorInner>, ServiceTierAdvisorInner>() {
              @Override
              public ServiceTierAdvisorInner call(ServiceResponse<ServiceTierAdvisorInner> response) {
                  return response.body();
              }
          });
      }
docs: Gets a service tier advisor.
  
  @param resourceGroupName The name of the resource group that contains the resource. You can obtain this value from the Azure Resource Manager API or the portal.
  @param serverName The name of the server.
  @param databaseName The name of database.
  @param serviceTierAdvisorName The name of service tier advisor.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the ServiceTierAdvisorInner object