如何在Xamarin表单中创建一个Httpclient实例

using System.Net.Http;

private HttpClient httpClient = new HttpClient();

public MyClass()
{
    // 设置超时时间为10秒
    httpClient.Timeout = TimeSpan.FromSeconds(10);
    
    // 添加自定义请求头
    httpClient.DefaultRequestHeaders.Add("User-Agent", "MyApp");
}

public async Task<string> GetResponseAsync()
{
    string url = "https://example.com/api";
    
    HttpResponseMessage response = await httpClient.GetAsync(url);
    response.EnsureSuccessStatusCode(); // 确保请求成功
    
    string responseBody = await response.Content.ReadAsStringAsync();
    
    return responseBody;
}

httpClient.Dispose();