C#, HttpClient で Json を POST するときの Media-Type の設定方法

[Fact]
public async void TestMethod1()
{
    var dummmyURL = "";
    var dummyJson = "";

    using (var client = new HttpClient())
    {
        var response = await client.PostAsync(dummmyURL,
            new StringContent(dummyJson, Encoding.UTF8, "application/json-patch+json"));
    }

}