code: public List<VirtualMachineSizeInner> listAvailableSizes(String resourceGroupName, String vmName) {
          return listAvailableSizesWithServiceResponseAsync(resourceGroupName, vmName).toBlocking().single().body();
      }
docs: Lists all available virtual machine sizes to which the specified virtual machine can be resized.
  
  @param resourceGroupName The name of the resource group.
  @param vmName The name of the virtual machine.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws CloudException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the List&lt;VirtualMachineSizeInner&gt; object if successful.