Add refund section for swap-in

src/guide/receive_onchain.md

@@ -79,6 +79,7 @@ The `swap_info` above includes maximum and minimum limits. Your application's us
 
 </div>
 
+
 ## Get the in-progress Swap
 
 Once you've sent the funds to the above address, the SDK will monitor this address for unspent confirmed outputs and use a trustless submarine swap to receive these into your Lightning node. You can always monitor the status of the current in-progress swap using the following code:
@@ -295,6 +296,13 @@ Once you have a refundable swap in hand, use the following code to execute a ref
 </section>
 </custom-tabs>
 
+<div class="warning">
+<h4>Developer note</h4>
+
+A refund can be issued several times. A common scenario where this is useful is if the initial refund transaction takes too long to mine, your application's users can be offered the ability to re-trigger the refund with a higher feerate.
+
+</div>
+
 # Calculating fees
 
 When the amount to be received exceeds the inbound liquidity of the node, a new channel will be opened by the LSP in order for the node to receive it. This can checked by retrieving the NodeState from the SDK and comparing the inbound liquidity to the amount to be received. If the amount is greater or equal to the inbound liquidity, a new channel opening is required.