- /// Optionally, when `output.block_hash` is set, should return any transaction spending the
- /// output that is found in the corresponding block along with its index.
- ///
- /// This return value is useful for Electrum clients in order to supply in-block descendant
- /// transactions which otherwise were not included. This is not necessary for other clients if
- /// such descendant transactions were already included (e.g., when a BIP 157 client provides the
- /// full block).
- #[must_use]
- pub register_output: extern "C" fn (this_arg: *const c_void, output: crate::lightning::chain::WatchedOutput) -> crate::c_types::derived::COption_C2Tuple_usizeTransactionZZ,
+ /// Note that this method might be called during processing of a new block. You therefore need
+ /// to ensure that also dependent output spents within an already connected block are correctly
+ /// handled, e.g., by re-scanning the block in question whenever new outputs have been
+ /// registered mid-processing.
+ pub register_output: extern "C" fn (this_arg: *const c_void, output: crate::lightning::chain::WatchedOutput),