Using fetch api to send a POST request to your own web server takes time

import http.server

class MyHandler (http.server.BaseHTTPRequestHandler):
    protocol_version = "HTTP/1.1"
    def do_POST(self):
        # Now this method just print path and content-type.
        print("POSTED")
        content_type=self.headers ["Content-Type"]
        print(content_type)
        print(self.path)
        if "multipart/form-data" in content_type:
            raw_data=self.rfile.read()
        self.send_response(200,self.responses[200][0])
        self.send_header("access-control-allow-origin", "*")
        self.end_headers()
        # WIP:do something...

    def do_GET(self):
        if self.path[0]=="/":
            self.path = self.path [1:]
        try:
            with open(self.path, "rb") asf:
                file_data=f.read()
        except FileNotFoundError:
            self.send_response(404, self.responses[404][0])
            self.end_headers()
            return
        print(file_data)
        content_length=len(file_data)
        self.send_response(200,self.responses[200][0])
        self.send_header("content-length", content_length)
        self.end_headers()
        self.wfile.write(file_data)

    def parse_post():
        # WIP
        pass

httpd=http.server.HTTPServer(",6788), MyHandler)
print("Address:", "", "Port:", 6788)
httpd.serve_forever()

let myheaders=new Headers();
myheaders.append("content-type", "multipart/form-data");
let formdata = new FormData();
formdata.append("Hello", "World");
fetch("http://localhost:6788/nk", {
    method: "POST",
    mode: "cors",
    body:formdata,
    header —myheaders
}).then(response)=>response.text()) .then(text)=>console.log(text));