* `seek(versatz)`: Geht zur Position `versatz` (`int`) in der Datei.
    * Z. B. würde `await myfile.seek(0)` zum Anfang der Datei gehen.
    * Das ist besonders dann nützlich, wenn Sie `await myfile.read()` einmal ausführen und dann diese Inhalte erneut auslesen müssen.
* `close()`: Schließt die Datei.

Da alle diese Methoden `async`hron sind, müssen Sie sie „await“en („erwarten“).

In this type of scenario, you probably would want to have **a single (Uvicorn) process per container**, as you would already be handling replication at the cluster level.

So, in this case, you **would not** want to have a multiple workers in the container, for example with the `--workers` command line option. You would want to have just a **single Uvicorn process** per container (but probably multiple containers).

///

## Aguarde mensagens e envie mensagens { #await-for-messages-and-send-messages }

Em sua rota WebSocket você pode esperar (`await`) por mensagens e enviar mensagens.

{* ../../docs_src/websockets/tutorial001_py39.py hl[48:52] *}

Você pode receber e enviar dados binários, de texto e JSON.

## Do not Separate Schemas { #do-not-separate-schemas }

Now, there are some cases where you might want to have the **same schema for input and output**.

Probably the main use case for this is if you already have some autogenerated client code/SDKs and you don't want to update all the autogenerated client code/SDKs yet, you probably will want to do it at some point, but maybe not right now.

                use_astack = function_astack
            solved = await _solve_generator(
                dependant=use_sub_dependant,
                stack=use_astack,
                sub_values=solved_result.values,
            )
        elif use_sub_dependant.is_coroutine_callable:
            solved = await call(**solved_result.values)
        else:
            solved = await run_in_threadpool(call, **solved_result.values)

			t.Errorf("Test %d: filtered headers do not match expected headers - got: %v , want: %v", i, test.Header, test.ExpectedHeader)
		}
		RemoveSensitiveEntries(metadata)
		if !areKeysEqual(test.ExpectedHeader, metadata) {
			t.Errorf("Test %d: filtered headers do not match expected headers - got: %v , want: %v", i, test.Header, test.ExpectedHeader)
		}
	}

## Decision

The *Build Tool Team* has decided to use Architectural Decision Records (aka ADR) to track decisions we want to follow.

The main logic with ADRs is to describe (architectural) decisions made:

* To provide best practices and solutions we (as the *build tool* team) want to promote.
* To avoid asking the same thing multiple times during code review.

This is probably not as important or necessary if you use `Annotated`.

///

Let's say that you want to declare the query parameter `q` as a required `str`.

And you don't need to declare anything else for that parameter, so you don't really need to use `Query`.

But you still need to use `Path` for the `item_id` path parameter. And you don't want to use `Annotated` for some reason.

                    type.defaultBaselines,
                    display = ParameterDisplay.PROMPT,
                    allowEmpty = true,
                    description = "The baselines you want to run performance tests against. Empty means default baseline.",
                )
                param("env.PERFORMANCE_STAGE", stage.stageName.toString())

Let's say you have a custom exception `UnicornException` that you (or a library you use) might `raise`.

And you want to handle this exception globally with FastAPI.

You could add a custom exception handler with `@app.exception_handler()`:

{* ../../docs_src/handling_errors/tutorial003_py39.py hl[5:7,13:18,24] *}