_group_session sess key key_len pickled pickled_len</code></p><p>Stores a group session as a base64 string. Encrypts the session using the supplied key. Returns the length of the session on success.</p><p>Returns olm_error() on failure. If the pickle output buffer is smaller than olm_pickle_outbound_group_session_length() then olm_outbound_group_session_last_error() will be &quot;OUTPUT_BUFFER_TOO_SMALL&quot;</p></dd></dl><dl><dt class="spec value" id="val-unpickle_outbound_group_session"><a href="#val-unpi