Also, the best approach was to use already existing standards.

So, before even starting to code **FastAPI**, I spent several months studying the specs for OpenAPI, JSON Schema, OAuth2, etc. Understanding their relationship, overlap, and differences.

## Design

Then I spent some time designing the developer "API" I wanted to have as a user (as a developer using FastAPI).

       *
       * Android API level 26 and JVM8 both let our Error propagate directly the first time and
       * throw NoClassDefFoundError thereafter. This is the proper behavior according to the spec.
       * See https://docs.oracle.com/javase/specs/jls/se8/html/jls-12.html#jls-12.4.2 (steps #11 and
       * #5).
       *
       * Note that that "first time" might happen in a test other than
       * testLexicographicalComparatorChoice!

## Technical Details

Just a technical detail for the curious nerds. 🤓

Underneath, in the ASGI technical specification, this is part of the <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">Lifespan Protocol</a>, and it defines events called `startup` and `shutdown`.

!!! info

       *
       * Android API level 26 and JVM8 both let our Error propagate directly the first time and
       * throw NoClassDefFoundError thereafter. This is the proper behavior according to the spec.
       * See https://docs.oracle.com/javase/specs/jls/se8/html/jls-12.html#jls-12.4.2 (steps #11 and
       * #5).
       *
       * Note that that "first time" might happen in a test other than
       * testLexicographicalComparatorChoice!

## Technische Details

Nur ein technisches Detail für die neugierigen Nerds. 🤓

In der technischen ASGI-Spezifikation ist dies Teil des <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">Lifespan Protokolls</a> und definiert Events namens `startup` und `shutdown`.

!!! info

## Detalhes técnicos

Só um detalhe técnico para nerds curiosos. 🤓

Por baixo, na especificação técnica ASGI, essa é a parte do <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">Protocolo Lifespan</a>, e define eventos chamados `startup` e `shutdown`.

!!! info "Informação"

          " supported protocols=${sslSocket.enabledProtocols!!.contentToString()}",
      )
  }

  /**
   * Returns a copy of this connection with the next connection spec to try, or null if no other
   * compatible connection specs are available.
   */
  internal fun nextConnectionSpec(
    connectionSpecs: List<ConnectionSpec>,
    sslSocket: SSLSocket,
  ): ConnectPlan? {

🔨 👈 👽 🔢 👈 🚫 💰 ⚛ ⚖️ 🔢 👯‍♂️ 🌅 ⚠ 👆 🔜 💪 🏪 💲 🌐 🔢 ⚖️ 🎏 🎱.

↩️ 👈, ⚫️ 🔜 👍 ↩️ ⚙️ `lifespan` 🔬 🔛.

## 📡 ℹ

📡 ℹ 😟 🤓. 👶

🔘, 🔫 📡 🔧, 👉 🍕 <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">🔆 🛠️</a>, &amp; ⚫️ 🔬 🎉 🤙 `startup` &amp; `shutdown`.

## 🎧 🈸

			case *ast.GenDecl:
				if isDeprecated(n.Doc) {
					for _, spec := range n.Specs {
						switch spec := spec.(type) {
						case *ast.ValueSpec:
							for _, id := range spec.Names {
								mark(id)
							}
						case *ast.TypeSpec:
							mark(spec.Name)
						}
					}
				}
				return true // look at specs
			case *ast.FuncDecl:
				if isDeprecated(n.Doc) {
					mark(n.Name)

  // but essentially each line will be a call to a Preconditions method that, but for a documented
  // change would be a compiler error.
  // See http://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.12.2 for the spec on
  // how javac selects overloads
  @SuppressWarnings("null")
  public void overloadSelection() {
    Boolean boxedBoolean = null;
    boolean aBoolean = true;
    Long boxedLong = null;