bool silc_client_send_channel_message(SilcClient client,
                                          SilcClientConnection conn,
                                          SilcChannelEntry channel,
                                          SilcChannelPrivateKey key,
                                          SilcMessageFlags flags,
                                          unsigned char *data,
                                          SilcUInt32 data_len,
                                          bool_force_send);

    Sends packet to the `channel'. Packet to channel is always encrypted
    differently from "normal" packets. SILC header of the packet is
    encrypted with the next receiver's key and the rest of the packet is
    encrypted with the channel specific key. Padding and HMAC is computed
    with the next receiver's key. The `data' is the channel message. If
    the `force_send' is TRUE then the packet is sent immediately.

    If `key' is provided then that private key is used to encrypt the
    channel message.  If it is not provided, private keys has not been
    set at all, the normal channel key is used automatically.  If private
    keys are set then the first key (the key that was added first as
    private key) is used.

    If the `flags' includes SILC_MESSAGE_FLAG_SIGNED the message will be
    digitally signed with the SILC key pair.

    Returns TRUE if the message was sent, and FALSE if error occurred or
    the sending is not allowed due to channel modes (like sending is
    blocked).