Add benchmark result for x-unet?

[BIGBALLON]

Hi, @lucidrains, thanks for your great repo, I just wonder if you have the plan to add some benchmark testing results of your x-net,(PSACL VOC, COCO, ADE20K, etc.) or some advice/docs about the performance of x-net.
This is really helpful for everyone to select the correct network.

Many thanks again!