using RestSharp;


var options = new RestClientOptions("http://localhost:56350/api/v1/List/{udListDefinitionId}/Items");
var client = new RestClient(options);
var request = new RestRequest("");
var response = await client.DeleteAsync(request);

Console.WriteLine("{0}", response.Content);

const options = {method: 'DELETE'};

fetch('http://localhost:56350/api/v1/List/{udListDefinitionId}/Items', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_PORT => "56350",
  CURLOPT_URL => "http://localhost:56350/api/v1/List/{udListDefinitionId}/Items",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "DELETE",
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

import requests

url = "http://localhost:56350/api/v1/List/{udListDefinitionId}/Items"

response = requests.delete(url)

print(response.text)

const options = {method: 'DELETE'};

fetch('http://localhost:56350/api/v1/List/{udListDefinitionId}/Items', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));