How to configure cwebp-metadata all via options

[givebest]

How to achieve the same results as cwebp -metadata all with options configuration.

[dreampiggy]

Currently the Encoding API does not keep metadata. Which need some API break changes from SDWebImage Core repo.

In the last year I have a prototype for this, by using a new class SDImageMetadata and use some API like addImage:UIImage metadata:SDImageMetadata. But it's not finished yet.