//TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may
// have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after OutboundV1Channel::get_funding_created,
// before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
//TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may
// have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after OutboundV1Channel::get_funding_created,
// before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing