Set the rate-limit of a the bufferevent 'bev' to the one specified in
'cfg'. If 'cfg' is NULL, disable any per-bufferevent rate-limiting on
'bev'.
Note that only some bufferevent types currently respect rate-limiting.
They are: socket-based bufferevents (normal and IOCP-based), and SSL-based
bufferevents.
Set the rate-limit of a the bufferevent 'bev' to the one specified in 'cfg'. If 'cfg' is NULL, disable any per-bufferevent rate-limiting on 'bev'.
Note that only some bufferevent types currently respect rate-limiting. They are: socket-based bufferevents (normal and IOCP-based), and SSL-based bufferevents.
Return 0 on sucess, -1 on failure.