f: arbitrarily determine the Trampoline keysend TLV ID to be 20, because why not

Author: arik-so

lightning/src/ln/msgs.rs

@@ -2810,15 +2810,14 @@ impl<'a> Writeable for OutboundTrampolinePayload<'a> {
 				});
 			},
 			Self::BlindedReceive { sender_intended_htlc_amt_msat, total_msat, cltv_expiry_height, encrypted_tlvs, intro_node_blinding_point, keysend_preimage, custom_tlvs } => {
-				let keysend_tlv = keysend_preimage.map(|preimage| (5482373484, preimage.encode()));
-				let mut custom_tlvs: Vec<&(u64, Vec<u8>)> = custom_tlvs.iter().chain(keysend_tlv.iter()).collect();
-				custom_tlvs.sort_unstable_by_key(|(typ, _)| *typ);
+				let keysend_tlv = keysend_preimage.map(|preimage| preimage.encode());
 				_encode_varint_length_prefixed_tlv!(w, {
 					(2, HighZeroBytesDroppedBigSize(*sender_intended_htlc_amt_msat), required),
 					(4, HighZeroBytesDroppedBigSize(*cltv_expiry_height), required),
 					(10, **encrypted_tlvs, required_vec),
 					(12, intro_node_blinding_point, option),
-					(18, HighZeroBytesDroppedBigSize(*total_msat), required)
+					(18, HighZeroBytesDroppedBigSize(*total_msat), required),
+					(20, keysend_tlv, option)
 				}, custom_tlvs.iter());
 			}
 		}