app = FastAPI()

app.add_middleware(UnicornMiddleware, some_config="rainbow")
```

`app.add_middleware()` receives a middleware class as the first argument and any additional arguments to be passed to the middleware.

## Integrated middlewares { #integrated-middlewares }

**FastAPI** includes several middlewares for common use cases, we'll see next how to use them.

/// note | Technical Details

    // Common return codes from MS-SWN specification
    /** Operation completed successfully */
    public static final int ERROR_SUCCESS = 0x00000000;
    /** Invalid parameter was passed to the operation */
    public static final int ERROR_INVALID_PARAMETER = 0x00000057;
    /** Buffer provided is insufficient */
    public static final int ERROR_INSUFFICIENT_BUFFER = 0x0000007A;

			scannerLogOnceIf(ctx, err, dataUsageObjNamePath)
		}
		attempts++
	}
}

var prefixUsageCache = cachevalue.New[map[string]uint64]()

// loadPrefixUsageFromBackend returns prefix usages found in passed buckets
//
//	e.g.:  /testbucket/prefix => 355601334
func loadPrefixUsageFromBackend(ctx context.Context, objAPI ObjectLayer, bucket string) (map[string]uint64, error) {
	z, ok := objAPI.(*erasureServerPools)
	if !ok {

			err = erasure.DecodeDataAndParityBlocks(t.Context(), encoded)
		} else {
			err = erasure.DecodeDataBlocks(encoded)
		}

		if err == nil && test.shouldFail {
			t.Errorf("Test %d: test should fail but it passed", i)
		}
		if err != nil && !test.shouldFail {
			t.Errorf("Test %d: test should pass but it failed: %v", i, err)
		}

		decoded := encoded
		if !test.shouldFail {
			if test.reconstructParity {

       */
      seenExceptionsLocal = requireNonNull(seenExceptionsField);
    }
    return seenExceptionsLocal;
  }

  /** Populates {@code seen} with the exception that was passed to {@code setException}. */
  abstract void addInitialException(Set<Throwable> seen);

  final int decrementRemainingAndGet() {
    return ATOMIC_HELPER.decrementAndGetRemainingCount(this);
  }

        // Verify close was called
        verify(mockHandle, times(1)).sendrecv(any(MsrpcSamrCloseHandle.class));
        assertEquals(handle, closeCaptor.getValue().handle); // Verify correct handle is passed
    }

    @Test
    void testClose_AlreadyClosed() throws IOException {
        // Test case: close() when already closed, should do nothing
        String server = "testServer";
        int access = 123;

        verify(locator).handleDFSReferral(referral, null);
        verifyNoMoreInteractions(locator);
    }

    // Interaction detail: capture arguments passed to handleDFSReferral
    @Test
    @DisplayName("handleDFSReferral receives the exact arguments via captor")
    void handleDfsReferralArgumentCapture() {

        assertSame(dummy, ua.getAddress(), "constructor should store the supplied address");
    }

    @Test
    void constructorRejectsNull() {
        // Expect constructor to throw IllegalArgumentException when passed null
        assertThrows(IllegalArgumentException.class, () -> new UniAddress(null));
    }

    /* ---------------------------------------------------------------------
     * 2. Value based tests for instance methods

	}
	tm.incrementBytes(bytes)
	m.bucketsMeasurement[opts] = tm
}

// SelectionFunction for buckets
type SelectionFunction func(bucket string) bool

// SelectBuckets will select all the buckets passed in.
func SelectBuckets(buckets ...string) SelectionFunction {
	if len(buckets) == 0 {
		return func(bucket string) bool {
			return true
		}
	}
	return func(bucket string) bool {

   */
  public static <E extends Enum<E>> EnumMultiset<E> create(Iterable<E> elements) {
    Iterator<E> iterator = elements.iterator();
    checkArgument(iterator.hasNext(), "EnumMultiset constructor passed empty Iterable");
    EnumMultiset<E> multiset = new EnumMultiset<>(iterator.next().getDeclaringClass());
    Iterables.addAll(multiset, elements);
    return multiset;
  }

  /**