Custom memory BIO write callback, determine last segment?
I have a custom BIO_TYPE_MEM BIO with write and read callbacks that map to a networking socket. I'm getting a lot better performance by using the MSG_MORE flag of the Linux send syscall to "cork" segments of a stream together.
So far I have guessed whether to pass MSG_MORE or not based of the size of the chunk passed to the BIO write callback, but this is no longer viable.
SSL_write with a long buffer will produce roughly 16kb chunks to be sent off by the BIO - how can I know if a chunk is "in the middle" of an ongoing SSL_write or if the chunk is last?
I don't see anything that can help me in the BIO ctrl callback, or?