SilcChannelEntry
    silc_client_get_channel_by_id(SilcClient client,
                                  SilcClientConnection conn,
                                  SilcChannelID *channel_id);

    Finds channel entry by the channel ID. Returns the entry or NULL
    if the entry was not found.  This checks the local cache and does
    not resolve anything from server.

    The returned SilcChannelEntry has been referenced by the library and
    the caller must call silc_client_unref_channel after the entry is not
    needed anymore.