Refactor: HTTP clients, unified HTTP2/QUIC options, Apple engines

common/httpclient/context.go

@@ -0,0 +1,14 @@
+package httpclient
+
+import "context"
+
+type transportKey struct{}
+
+func contextWithTransportTag(ctx context.Context, transportTag string) context.Context {
+	return context.WithValue(ctx, transportKey{}, transportTag)
+}
+
+func transportTagFromContext(ctx context.Context) (string, bool) {
+	value, loaded := ctx.Value(transportKey{}).(string)
+	return value, loaded
+}