## Technical Details { #technical-details }

/// tip

If you are already using **FastAPI** version **0.99.0 or above**, you can probably **skip** these details.

They are more relevant for older versions, before OpenAPI 3.1.0 was available.

You can consider this a brief OpenAPI and JSON Schema **history lesson**. 🤓

///

/// warning

it defaults to `panicnil=0`, making `panic(nil)` a run-time error.
Using `panicnil=1` restores the behavior of Go 1.20 and earlier.

When compiling a work module or workspace that declares
an older Go version, the Go toolchain amends its defaults
to match that older Go version as closely as possible.
For example, when a Go 1.21 toolchain compiles a program,
if the work module's `go.mod` or the workspace's `go.work`

col-12{-ms-flex:0 0 100%;flex:0 0 100%;max-width:100%}.order-first{-ms-flex-order:-1;order:-1}.order-last{-ms-flex-order:13;order:13}.order-0{-ms-flex-order:0;order:0}.order-1{-ms-flex-order:1;order:1}.order-2{-ms-flex-order:2;order:2}.order-3{-ms-flex-order:3;order:3}.order-4{-ms-flex-order:4;order:4}.order-5{-ms-flex-order:5;order:5}.order-6{-ms-flex-order:6;order:6}.order-7{-ms-flex-order:7;order:7}.order-8{-ms-flex-order:8;order:8}.order-9{-ms-flex-order:9;order:9}.order-10{-ms-flex-order:10...

	xlHeader = [4]byte{'X', 'L', '2', ' '}

	// Current version being written.
	xlVersionCurrent [4]byte
)

const (
	// Breaking changes.
	// Newer versions cannot be read by older software.
	// This will prevent downgrades to incompatible versions.
	xlVersionMajor = 1

	// Non breaking changes.
	// Bumping this is informational, but should be done

Es steht Ihnen **frei**, das zu verwenden, was Sie möchten, **FastAPI** legt Ihnen keine Einschränkungen auf.

Aber dieser Leitfaden zeigt Ihnen mehr oder weniger, wie die beiden normalerweise verwendet werden.

///

### Pydantics `exclude_unset`-Parameter verwenden { #using-pydantics-exclude-unset-parameter }

  /** The socket that carries this web socket. This is canceled when the web socket fails. */
  private var socket: Socket? = null

  /** Outgoing pongs in the order they should be written. */
  private val pongQueue = ArrayDeque<ByteString>()

  /** Outgoing messages and close frames in the order they should be written. */
  private val messageAndCloseQueue = ArrayDeque<Any>()

        // We add ordering between internal phases.
        // This would be wrong at execution time, but we are here computing a list and not a graph,
        // so in order to obtain the expected order, we add these links between phases.
        Lifecycle.Phase prev = null;
        for (Lifecycle.Phase child : phases) {
            // add phase
            addPhase(graph, before, after, child);

     * {@link NtTransQuerySecurityDesc#writeParametersWireFormat(byte[], int)}.
     */
    private static byte[] expectedParameters(int fid, int securityInformation) {
        ByteBuffer bb = ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN);
        bb.putShort((short) fid);
        bb.put((byte) 0x00); // Reserved
        bb.put((byte) 0x00); // Reserved
        bb.putInt(securityInformation);
        return bb.array();
    }

         * NOTE: This is primarily to keep backward-compat with Maven 2.x which did not validate that dependencies are
         * unique within a single POM. Upon multiple declarations, 2.x just kept the last one but retained the order of
         * the first occurrence. So when we're in lenient/compat mode, we have to deal with such broken POMs and mimic

///

## Birden Fazla Middleware Çalıştırma Sırası { #multiple-middleware-execution-order }