Explain the concept of Stateless in the context of developing server applications and services.

The Stateless concept in server applications means that each request from a client to the server is processed independently, without storing information about previous requests. The server does not maintain session state between requests, which simplifies scaling and increases fault tolerance.

For example, in REST API, each HTTP request contains all the necessary information for processing (such as authentication data, parameters), and the server does not depend on previous client requests.

In Go, this is often implemented through HTTP request handlers that do not use global or session variables to store state between calls:

func handler(w http.ResponseWriter, r *http.Request) {
    // Process the request based on data from r
    // No state is stored between calls
    fmt.Fprintf(w, "Hello, %s!", r.URL.Query().Get("name"))
}

This approach facilitates horizontal scaling and simplifies application maintenance.