Creates a new out-bound session for sending messages to a given identity_key
* and one_time_key. Returns olm_error() on failure. If the keys couldn't be
* decoded as base64 then olm_session_last_error() will be "INVALID_BASE64"
* If there weren't enough random bytes then olm_session_last_error() will
* be "NOT_ENOUGH_RANDOM".
Creates a new out-bound session for sending messages to a given identity_key * and one_time_key. Returns olm_error() on failure. If the keys couldn't be * decoded as base64 then olm_session_last_error() will be "INVALID_BASE64" * If there weren't enough random bytes then olm_session_last_error() will * be "NOT_ENOUGH_RANDOM".