e length of the encrypted message or olm_error() on failure. On failure last_error will be set with an error code. The last_error will be OUTPUT_BUFFER_TOO_SMALL if the output buffer is too small.</p></dd></dl><dl><dt class="spec value" id="val-outbound_group_session_id_length"><a href="#val-outbound_group_session_id_length" class="anchor"></a><code><span class="keyword">val</span> outbound_group_session_id_length : <span><a href="../Types/OutboundGroupSession/index.html#type-t">Types.OutboundGroupSession.t