code: public Request createPostRequest(String url, Map<String, Object> params, String apiKey, String accessToken) {
          FormBody.Builder builder = new FormBody.Builder();
          for(Map.Entry<String, Object> entry: params.entrySet()){
              builder.add(entry.getKey(), entry.getValue().toString());
          }
  
          RequestBody requestBody = builder.build();
          Request request = new Request.Builder().url(url).post(requestBody).header("User-Agent", USER_AGENT).header("X-Kite-Version", "3").header("Authorization", "token "+apiKey+":"+accessToken).build();
          return request;
      }
docs: Creates a POST request.
  @param url is the endpoint to which request has to be done.
  @param apiKey is the api key of the Kite Connect app.
  @param accessToken is the access token obtained after successful login process.
  @param params is the map of data that has to be sent in the body.