// create elegant application errors
err := app.NewErrorValidation("validate_user", "Error Validating User")
err.AddValidationError(NewFieldValidationError("name", "name is empty"))
err.AddValidationError(NewFieldValidationError("age", "user is under 18", "user must be an adult"))

// wrap the inner cause of the error
conn, err := db.Connect(...)

if err != nil {
   return app.NewErrorInternal("database_connection", "Error connecting to the database").SetSeverity(app.ErrorSeverityCritical).Wrap(err)
}

// create a raw error
err := app.NewError(("error_code", app.ErrorInternal, app.ErrorSeverityHigh, "Error message"))

// enriched context
func Hello(w http.ResponseWriter, r *http.Request) {
    ctx := app.FromContext(r.Context())
    traceId := appCtx.TraceID()
    userID, checkUser := ctx.UserID()

    if checkUser {
        //request authorized
    }
}

	var GetPersonTask = func() (Person, error) {
        var p Person
        resp, err := http.Get("http://example.com/")

        if err != nil {
            return p, err
        }

        err = json.NewDecoder(resp.Body).Decode(&p)

		return resp, err
	}

    config := retry.NewConfig(3)

	result, err := retry.Execute(config, task)

	clock := NewUtcClock()
	timeNowUtc := clock.Now().Format(time.RFC822)

	sleeper := sleep.New()
	sleeper.Sleep(1000)

	appCtx := app.FromContext(ctx)
	err := app.NewErrorValidation("invalid_payment_data", "The payment request is invalid")
	err.AddValidationError(app.NewFieldValidationError("amount", "Amount needs to be positive"))
	err.AddValidationError(app.NewFieldValidationError("currency", "currency is required"))

	httpErr := New(appCtx, err, "/payments")