Use WithReplyKey new() to generate a sender directly

Author: benalleng

payjoin/src/core/send/v2/mod.rs

@@ -169,13 +169,7 @@ impl SenderBuilder {
         pj_param: PjParam,
         psbt_ctx: PsbtContext,
     ) -> NextStateTransition<SessionEvent, Sender<WithReplyKey>> {
-        let reply_key = HpkeKeyPair::gen_keypair().0;
-        let sender = Sender {
-            state: WithReplyKey,
-            pj_param: pj_param.clone(),
-            psbt_ctx: psbt_ctx.clone(),
-            reply_key: reply_key.clone(),
-        };
+        let sender = Sender::new(pj_param, psbt_ctx);
         NextStateTransition::success(SessionEvent::Created(Box::new(sender.clone())), sender)
     }
 }
@@ -261,6 +255,10 @@ impl SendSession {
 pub struct WithReplyKey;
 
 impl Sender<WithReplyKey> {
+    fn new(pj_param: PjParam, psbt_ctx: PsbtContext) -> Self {
+        Sender { state: WithReplyKey, pj_param, psbt_ctx, reply_key: HpkeKeyPair::gen_keypair().0 }
+    }
+
     /// Construct serialized Request and Context from a Payjoin Proposal.
     ///
     /// Important: This request must not be retried or reused on failure.