## Background and motivation

Motivations to implement ztunnel generally came from two areas.

First, and most importantly, it serves as a means to implement the real goal: waypoints.
For various reasons outside the scope of this document, there is a desire to move from a sidecar based architecture to a "remote proxy" architecture.

Luego, cuando llega tu turno, haces un trabajo "productivo" real 🤓, procesas el menú, decides lo que quieres, lo que quiere esa persona 😍, pagas 💸, verificas que das el billete o tarjeta correctos, verificas que te cobren correctamente, que el pedido tiene los artículos correctos, etc.

            this.realm = p.getProperty("jcifs.http.basicRealm");
            this.netbiosLookupRespLimit = Config.getInt(p, "jcifs.netbios.lookupRespLimit", 3);
            this.netbiosCacheTimeout = Config.getInt(p, "jcifs.netbios.cachePolicy", 60 * 10) * 60; /* 10 hours */

            if ( this.realm == null )
                this.realm = "jCIFS";

    // Trigger any exception that the comparator would throw for the endpoints.
    /*
     * uncheckedCastNullableTToT is safe as long as the callers are careful to pass a "real" T
     * whenever they pass `true` for the matching `has*Bound` parameter.
     */
    if (hasLowerBound) {
      int unused =
          comparator.compare(

      }
    }

    /*
     * TODO(cpovirk): `return (V) removedValue` once our checker permits that.
     *
     * (We promoted a class of warnings into errors because sometimes they indicate real problems.
     * But now we need to "undo" some instance of spurious errors, as discussed in
     * https://github.com/jspecify/checker-framework/issues/8.)
     */
    return removedValue == null ? null : (V) removedValue;

    hashed_password = hashed_password,
)
```

/// warning

As funções adicionais de suporte são apenas para demonstração de um fluxo possível dos dados, mas é claro que elas não fornecem segurança real.

///

## Reduzir duplicação

Reduzir a duplicação de código é uma das ideias principais no **FastAPI**.

                    return null;
                }
                else if ( this.isDataFromNodeStatus ) {
                    /*
                     * 'this' has been updated and should now
                     * have a real NetBIOS name
                     */
                    this.calledName = null;
                    return getHostName();
                }
            }
            catch ( UnknownHostException uhe ) {

For this simple example, we are going to just be completely insecure and return the same `username` as the token.

/// tip

In the next chapter, you will see a real secure implementation, with password hashing and <abbr title="JSON Web Tokens">JWT</abbr> tokens.

But for now, let's focus on the specific details we need.

///

//// tab | Python 3.10+

    // Trigger any exception that the comparator would throw for the endpoints.
    /*
     * uncheckedCastNullableTToT is safe as long as the callers are careful to pass a "real" T
     * whenever they pass `true` for the matching `has*Bound` parameter.
     */
    if (hasLowerBound) {
      int unused =
          comparator.compare(

  }

  dlm_tensor->dl_tensor.shape = shape_arr->data();
  // There are two ways to represent compact row-major data
  // 1) nullptr indicates tensor is compact and row-majored.
  // 2) fill in the strides array as the real case for compact row-major data.
  // Here we choose option 2, since some frameworks didn't handle the strides
  // argument properly.
  dlm_tensor->dl_tensor.strides = stride_arr->data();