You can send a multisearch template request with

```c#
var client = new ElasticClient();

var response = client.MultiSearchTemplate(ms => ms
    .Template<object>("template_1", st => st
        .AllIndices()
        .AllTypes()
        .Id("t1")
        .Params(d => d
            .Add("field", "Envrionment")
            .Add("value", "Test")
        )
    )
    .Template<object>("template_2", st => st
        .AllIndices()
        .AllTypes()
        .Id("t1")
        .Params(d => d
            .Add("field", "Envrionment")
            .Add("value", "Test")
        )
    )
);

var firstSearchResponse = response.GetResponse<object>("template_1");
var secondSearchResponse = response.GetResponse<object>("template_2");
```

I've used `object` here to represent the type to which the documents in each search will be deserialized into, but you can use whatever class makes sense.
This will send the following request

```json
POST http://localhost:9200/_msearch/template
{"index":"_all"}
{"id":"t1","params":{"field":"Envrionment","value":"Test"}}
{"index":"_all"}
{"id":"t1","params":{"field":"Envrionment","value":"Test"}}
```

Note that NEST inserts the `"_all"` index name for all indices, which should act the same as not specifying the index.

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