code: @Override
      public java.util.concurrent.Future<DescribeFileSystemsResult> describeFileSystemsAsync(
              com.amazonaws.handlers.AsyncHandler<DescribeFileSystemsRequest, DescribeFileSystemsResult> asyncHandler) {
  
          return describeFileSystemsAsync(new DescribeFileSystemsRequest(), asyncHandler);
      }
docs: Simplified method form for invoking the DescribeFileSystems operation with an AsyncHandler.
  
  @see #describeFileSystemsAsync(DescribeFileSystemsRequest, com.amazonaws.handlers.AsyncHandler)