chore: import upstream snapshot with attribution

transport/context.go

@@ -0,0 +1,20 @@
+package transport
+
+import (
+	"net"
+)
+
+type netListener struct{}
+
+// getNetListener Get net.Listener from ListenOptions.
+func getNetListener(o *ListenOptions) net.Listener {
+	if o.Context == nil {
+		return nil
+	}
+
+	if l, ok := o.Context.Value(netListener{}).(net.Listener); ok && l != nil {
+		return l
+	}
+
+	return nil
+}