Static MTLCommandBufferEncoderInfoErrorKey 

pub unsafe static MTLCommandBufferEncoderInfoErrorKey: &'static NSErrorUserInfoKey

Available on crate feature MTLCommandBuffer only.

Key in the userInfo for MTLCommandBufferError NSErrors. Value is an NSArray of MTLCommandBufferEncoderInfo objects in recorded order if an appropriate MTLCommandBufferErrorOption was set, otherwise the key will not exist in the userInfo dictionary.

See also Apple’s documentation