feat: add GetRootContextByID call

Author: wouterposdijk

proxywasm/hostcall.go

@@ -50,6 +50,14 @@ func GetCurrentTime() int64 {
 	return t
 }
 
+func GetRootContextByID(rootContextID uint32) (RootContext, error) {
+	rootContextState, ok := currentState.rootContexts[rootContextID]
+	if !ok {
+		return nil, types.ErrorStatusNotFound
+	}
+	return rootContextState.context, nil
+}
+
 func DispatchHttpCall(upstream string,
 	headers [][2]string, body string, trailers [][2]string,
 	timeoutMillisecond uint32, callBack HttpCalloutCallBack) (calloutID uint32, err error) {