isotp_user_debug() specifies varargs, but then avoids using it

[j3kestrel]

isotp_user.h defines isotp_user_debug() to use varargs:

void isotp_user_debug(const char* message, ...);

However, that feature is never used and is avoided in the only case where more than a simple immediate string is sent in isotp.c:isotp_send():

        char message[128];
        sprintf(&message[0], "Attempted to send %d bytes; max size is %d!\n", size, link->send_buf_size);
        isotp_user_debug(message);

If it is preferred to avoid use of varargs, the signature for isotp_user_debug() should not include it. If avoidance is not desired, then isotp_send() should not avoid it?

Preferences?

[lishen2]

The library is not avoid use of varargs, but we normally don't use varargs to assemble binary messages