client.BaseAddress = new Uri("http://myurl.com/’’);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"))
string username = "test";
string password = "test";
// HTTP POST
ApiToken input = new ApiToken { username = username, password = password };
var values = new Dictionary<string, string>
{
    { "username", username },
    { "password", password }
};
var content = new FormUrlEncodedContent(values);
HttpResponseMessage response = client.PostAsync("api/token/take", content).Result;

<?php
$param = array(
    'username' => 'test',
    'password' => 'test'
);

$url = 'http://myurl.com/api/token/take';
    $ch=curl_init($url);
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
    curl_setopt($ch, CURLOPT_POSTFIELDS, $param);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));
    $request=  curl_getinfo($ch);

    $result = curl_exec($ch);
    curl_close($ch);
    echo $result;
?>