Fixed h2c enable crash bug

- Moved h2c roundtripper to a dedicated module
- Fixed h2c enable crash bug

src/mod/dynamicproxy/modh2c/modh2c.go

@@ -0,0 +1,45 @@
+package modh2c
+
+/*
+	modh2c.go
+
+	This module is a simple h2c roundtripper for dpcore
+*/
+
+import (
+	"context"
+	"crypto/tls"
+	"net"
+	"net/http"
+	"time"
+
+	"golang.org/x/net/http2"
+)
+
+type H2CRoundTripper struct {
+}
+
+func NewH2CRoundTripper() *H2CRoundTripper {
+	return &H2CRoundTripper{}
+}
+
+// Example from https://github.com/thrawn01/h2c-golang-example/blob/master/cmd/client/main.go
+func (h2c *H2CRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
+	defer cancel()
+
+	req, err := http.NewRequestWithContext(ctx, req.Method, req.RequestURI, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	tr := &http2.Transport{
+		AllowHTTP: true,
+		DialTLSContext: func(ctx context.Context, network, addr string, cfg *tls.Config) (net.Conn, error) {
+			var d net.Dialer
+			return d.DialContext(ctx, network, addr)
+		},
+	}
+
+	return tr.RoundTrip(req)
+}