Encrypts a message using the session. Returns the length of the message in
* bytes on success. Writes the message as base64 into the message buffer.
* Returns olm_error() on failure. If the message buffer is too small then
* olm_session_last_error() will be "OUTPUT_BUFFER_TOO_SMALL". If there
* weren't enough random bytes then olm_session_last_error() will be
* "NOT_ENOUGH_RANDOM".
Encrypts a message using the session. Returns the length of the message in * bytes on success. Writes the message as base64 into the message buffer. * Returns olm_error() on failure. If the message buffer is too small then * olm_session_last_error() will be "OUTPUT_BUFFER_TOO_SMALL". If there * weren't enough random bytes then olm_session_last_error() will be * "NOT_ENOUGH_RANDOM".