/// warning

You can probably skip this.

These are very technical details of how **FastAPI** works underneath.

If you have quite some technical knowledge (coroutines, threads, blocking, etc.) and are curious about how FastAPI handles `async def` vs normal `def`, go ahead.

///

### Path operation functions { #path-operation-functions }

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[14:18] hl[14:15,17:18] *}

Usar `check_same_thread=False` permite que o FastAPI use o mesmo banco de dados SQLite em diferentes threads. Isso é necessário, pois **uma única requisição** pode usar **mais de uma thread** (por exemplo, em dependências).

    hand it off to another thread to write to it after `writeTo` returns.

    The `EventListener` may now see requests and responses interleaved in ways not previously
    permitted. For example, a listener may receive `responseHeadersStart()` followed by
    `requestBodyEnd()`, both on the same call. Such events may be triggered by different threads
    even for a single call.

 *       appropriate factory method for details. View collections such as {@link
 *       ImmutableMultiset#elementSet} iterate in the same order as the parent, except as noted.
 *   <li><b>Thread safety.</b> It is safe to access this collection concurrently from multiple
 *       threads.
 *   <li><b>Integrity.</b> This type cannot be subclassed outside this package (which would allow
 *       these guarantees to be violated).
 * </ul>
 *

          }

          System.out.println(response.body().string());
        }
      }
    ```

### Asynchronous Get ([.kt][AsynchronousGetKotlin], [.java][AsynchronousGetJava])

Download a file on a worker thread, and get called back when the response is readable. The callback is made after the response headers are ready. Reading the response body may still block. OkHttp doesn't currently offer asynchronous APIs to receive a response body in parts.

 * }
 *
 * <p>Instances of {@link ImmutableNetwork} do not implement {@link MutableNetwork} (obviously!) and
 * are contractually guaranteed to be unmodifiable and thread-safe.
 *
 * <p>The Guava User Guide has <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#building-graph-instances">more
 * information on (and examples of) building graphs</a>.
 *

   * </ul>
   *
   * <p>The overall principle is to continue to treat every checked exception as a checked
   * exception, every unchecked exception as an unchecked exception, and every error as an error. In
   * addition, the cause of any {@code ExecutionException} is wrapped in order to ensure that the
   * new stack trace matches that of the current thread.
   *

   * allow in normal conditions. This is enforced by "throttling" incoming requests as needed. For
   * example, we could compute the appropriate throttle time for an incoming request, and make the
   * calling thread wait for that time.
   *
   * The simplest way to maintain a rate of QPS is to keep the timestamp of the last granted
   * request, and ensure that (1/QPS) seconds have elapsed since then. For example, for a rate of

import java.util.stream.LongStream;

/**
 * A mutable object which accumulates double values and tracks some basic statistics over all the
 * values added so far. The values may be added singly or in groups. This class is not thread safe.
 *
 * @author Pete Gillin
 * @author Kevin Bourrillion
 * @since 20.0
 */
@J2ktIncompatible
@GwtIncompatible
public final class StatsAccumulator {
  /** Creates a new accumulator. */

 * }
 *
 * <p>Instances of {@link ImmutableValueGraph} do not implement {@link MutableValueGraph}
 * (obviously!) and are contractually guaranteed to be unmodifiable and thread-safe.
 *
 * <p>The Guava User Guide has <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#building-graph-instances">more
 * information on (and examples of) building graphs</a>.
 *