pub enum PaymentSendFailure {
/// A parameter which was passed to send_payment was invalid, preventing us from attempting to
/// send the payment at all. No channel state has been changed or messages sent to peers, and
pub enum PaymentSendFailure {
/// A parameter which was passed to send_payment was invalid, preventing us from attempting to
/// send the payment at all. No channel state has been changed or messages sent to peers, and