1、使用DoRequest/DoRequestAsync发送请求

var lowLevelClient = new ElasticLowLevelClient();
var stringResponse = lowLevelClient.DoRequest<StringResponse>(
    HttpMethod.POST, 
    "_search", 
    PostData.Serializable(new
    {
        query = new { match_all = new { } }
    }));  

2、通过.LowLevel调用DoRequest()发送请求

var client = new ElasticClient();
var stringResponse = client.LowLevel.DoRequest<StringResponse>(
    HttpMethod.POST, 
    "_search", 
    PostData.Serializable(new
    {
        query = new { match_all = new { } }
    }));

3、使用请求内的匿名类型弹性搜索(Search)查询DSL

var  lowlevelClient = new ElasticLowLevelClient();
var searchResponse = lowlevelClient.Search<string>("people", "person", new
{
    from = 0,
    size = 10,
    query = new
    {
        match = new
        {
            field = "firstName",
            query = "Martijn"
        }
    }
});
var successful = searchResponse.Success;
var responseJson = searchResponse.Body;