code: public Observable<FailoverGroupInner> beginFailoverAsync(String resourceGroupName, String serverName, String failoverGroupName) {
          return beginFailoverWithServiceResponseAsync(resourceGroupName, serverName, failoverGroupName).map(new Func1<ServiceResponse<FailoverGroupInner>, FailoverGroupInner>() {
              @Override
              public FailoverGroupInner call(ServiceResponse<FailoverGroupInner> response) {
                  return response.body();
              }
          });
      }
docs: Fails over from the current primary server to this server.
  
  @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 containing the failover group.
  @param failoverGroupName The name of the failover group.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the FailoverGroupInner object