f payment docs

Author: TheBlueMatt

lightning/src/blinded_path/payment.rs

@@ -621,7 +621,8 @@ pub struct Bolt12OfferContext {
 	///
 	/// Payment metadata is stored as a map from a numeric key to an arbitrary byte array value.
 	/// This allows for several types of metadata to be stored attached to a single payment. In the
-	/// future some optional features of LDK may use some keys.
+	/// future some optional features of LDK may use some keys. For the sake of conflict
+	/// reduction, those features will attempt to use keys in the range 128-256.
 	///
 	/// Note that because this is included in the payment onion, its size must be tightly
 	/// constrained. More than a few hundred bytes and the payment will be entirely unpayable (with
@@ -653,7 +654,8 @@ pub struct AsyncBolt12OfferContext {
 	///
 	/// Payment metadata is stored as a map from a numeric key to an arbitrary byte array value.
 	/// This allows for several types of metadata to be stored attached to a single payment. In the
-	/// future some optional features of LDK may use some keys.
+	/// future some optional features of LDK may use some keys. For the sake of conflict
+	/// reduction, those features will attempt to use keys in the range 128-256.
 	///
 	/// Note that because this is included in the payment onion, its size must be tightly
 	/// constrained. More than a few hundred bytes and the payment will be entirely unpayable (with
@@ -679,7 +681,8 @@ pub struct Bolt12RefundContext {
 	///
 	/// Payment metadata is stored as a map from a numeric key to an arbitrary byte array value.
 	/// This allows for several types of metadata to be stored attached to a single payment. In the
-	/// future some optional features of LDK may use some keys.
+	/// future some optional features of LDK may use some keys. For the sake of conflict
+	/// reduction, those features will attempt to use keys in the range 128-256.
 	///
 	/// Note that because this is included in the payment onion, its size must be tightly
 	/// constrained. More than a few hundred bytes and the payment will be entirely unpayable (with