Missing usbd_alloc_xfer and usbd_alloc_buffer man pages

[Farhan Khan]

Hi all!

Can someone please explain to me what usbd_alloc_xfer and usbd_alloc_buffer 
do? I do not believe there are manual pages for either of them. I read the 
code on bxr.su, but I want to make sure I understand the intention of it.

Thank,

- Farhan