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 }

When you declare a *path operation function* with normal `def` instead of `async def`, it is run in an external threadpool that is then awaited, instead of being called directly (as it would block the server).

                alternativeChannel.addPendingOperation(op);
                // Operation would be resent on alternative channel
                // For now, skip actual send implementation
            } catch (Exception e) {
                log.error("Failed to redistribute operation", e);
                // Notify waiting threads of failure if the operation supports it
                if (op instanceof CommonServerMessageBlock) {

import com.google.common.annotations.GwtCompatible;
import org.jspecify.annotations.NullUnmarked;

@GwtCompatible
@NullUnmarked
final class TestPlatform {
  static int reduceIterationsIfGwt(int iterations) {
    return iterations;
  }

  private TestPlatform() {}

* feature: funcionalidad
* sponsor: sponsor
* host (in a podcast): host
* request (as in HTTP request): request
* response (as in HTTP response): response
* path operation function: path operation function (do not translate to "función de operación de ruta")
* path operation: path operation (do not translate to "operación de ruta")
* path (as in URL path): path (do not translate to "ruta")
* query (as in URL query): query (do not translate to "consulta")

        String message = "LDAP operation failed";
        LdapOperationException exception = new LdapOperationException(message);

        assertEquals(message, exception.getMessage());
        assertNull(exception.getCause());
    }

    public void test_constructor_withMessageAndCause() {
        // Test constructor with message and cause
        String message = "LDAP operation failed with error";

  public void testRemove_nullKeyQueriesUnsupported() {
    try {
      assertFalse(getMap().remove(null, v3()));
    } catch (NullPointerException tolerated) {
      // since the operation would be a no-op, the exception is not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)

    /** Performs a GAS operation on {@link AbstractFutureState#waitersField}. */
    abstract @Nullable Waiter gasWaiters(AbstractFutureState<?> future, Waiter update);

    /** Performs a GAS operation on {@link AbstractFutureState#listenersField}. */
    abstract @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update);

    /** Performs a CAS operation on {@link AbstractFutureState#valueField}. */

  public void testRemove_nullKeyQueriesUnsupported() {
    try {
      assertFalse(getMap().remove(null, v3()));
    } catch (NullPointerException tolerated) {
      // since the operation would be a no-op, the exception is not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)

  public void testRemove_nullKeyQueriesUnsupported() {
    try {
      assertFalse(getMap().remove(null, v3()));
    } catch (NullPointerException tolerated) {
      // since the operation would be a no-op, the exception is not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)

  public void testRemove_nullKeyQueriesUnsupported() {
    try {
      assertFalse(getMap().remove(null, v3()));
    } catch (NullPointerException tolerated) {
      // since the operation would be a no-op, the exception is not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)