suspicious discarding of buffer
code for encoding here creates a new buffer called t35_buf then writes it... then clears it before it gets dropped?
https://github.com/xiph/rav1e/blob/b7bf39066ec4f004c9b9cdb81c91734ec2edfac7/src/encoder.rs#L3785-L3793
there is also the fact that this suspicously isn't writing to the packet directly but that can be for bit padding or whatever I am not too sure, but it seems pointless to clear the buffer before dropping unless the intention was to reuse said buffer if that wasn't the intention it probably would be good to implement by just pulling the buffers declaration out of the loop
It is a tiny buffer for metadata, potentially the clear can be omitted but I guess who wrote the code kept the pattern used everywhere.