These constants are generally useful, and are linked from
documentation, so should be exposed in any case.
/// Default expiry time as defined by [BOLT 11].
///
/// [BOLT 11]: https://github.com/lightningnetwork/lightning-rfc/blob/master/11-payment-encoding.md
-const DEFAULT_EXPIRY_TIME: u64 = 3600;
+pub const DEFAULT_EXPIRY_TIME: u64 = 3600;
/// Default minimum final CLTV expiry as defined by [BOLT 11].
///
/// [BOLT 11]: https://github.com/lightningnetwork/lightning-rfc/blob/master/11-payment-encoding.md
-const DEFAULT_MIN_FINAL_CLTV_EXPIRY: u64 = 18;
+pub const DEFAULT_MIN_FINAL_CLTV_EXPIRY: u64 = 18;
/// This function is used as a static assert for the size of `SystemTime`. If the crate fails to
/// compile due to it this indicates that your system uses unexpected bounds for `SystemTime`. You