lnutils: add RecvOrTimeout

This abstracts out a common pattern where we wait for a send on a
channel, and timeout otherwise.

lnutils/chan.go

@@ -0,0 +1,18 @@
+package lnutils
+
+import (
+	"fmt"
+	"time"
+)
+
+// RecvOrTimeout attempts to recv over chan c, returning the value. If the
+// timeout passes before the recv succeeds, an error is returned
+func RecvOrTimeout[T any](c <-chan T, timeout time.Duration) (*T, error) {
+	select {
+	case m := <-c:
+		return &m, nil
+
+	case <-time.After(timeout):
+		return nil, fmt.Errorf("timeout hit")
+	}
+}