More h3 wrap up

src/Http3Request.h

@@ -1,6 +1,22 @@
+extern "C" {
+#include "quic.h"
+}
+
 namespace uWS {
 
     struct Http3Request {
-        // really the same thing as HttpRequest with same rules
+
+        std::string_view getHeader(std::string_view key) {
+            for (int i = 0, more = 1; more; i++) {
+                char *name, *value;
+                int name_length, value_length;
+                if (more = us_quic_socket_context_get_header(nullptr, i, &name, &name_length, &value, &value_length)) {
+                    if (name_length == key.length() && !memcmp(name, key.data(), key.length())) {
+                        return {value, value_length};
+                    }
+                }
+                return {nullptr, 0};
+            }
+        }
     };
 }