Clarify dtls1_do_write's interaction with the buffering BIO.

The existing comments are not very helpful. This code is also quite buggy.
Document two of them as TODOs.

Change-Id: Idfaf93d9c3b8b1ee92f2fb0d292ef513b5f6d824
Reviewed-on: https://boringssl-review.googlesource.com/2830
Reviewed-by: Adam Langley <agl@google.com>
1 file changed