*
 * ### Android Cleartext Permit Detection
 *
 * Supported on Android 6.0+ via `NetworkSecurityPolicy`.
 */
open class Platform {
  /** Prefix used on custom headers. */
  fun getPrefix() = "OkHttp"

  open fun newSSLContext(): SSLContext = SSLContext.getInstance("TLS")

  open fun platformTrustManager(): X509TrustManager {
    val factory =
      TrustManagerFactory.getInstance(

   */
  open fun callStart(call: Call) {
  }

  /**
   * Invoked prior to a proxy selection.
   *
   * This will be invoked for route selection regardless of whether the client
   * is configured with a single proxy, a proxy selector, or neither.
   *
   * @param url a URL with only the scheme, hostname, and port specified.
   */
  open fun proxySelectStart(
    call: Call,

    } else {
      eventSequence.forEach loop@{
        when (e.closes(it)) {
          null -> return // no open event
          true -> return // found open event
          false -> return@loop // this is not the open event so continue
        }
      }
      Assertions.fail<Any>("event $e without matching start event")
    }
  }

  override fun connectStart(

  /**
   * Invoked when an event source has been accepted by the remote peer and may begin transmitting
   * events.
   */
  open fun onOpen(
    eventSource: EventSource,
    response: Response,
  ) {
  }

  /**
   * TODO description.
   */
  open fun onEvent(
    eventSource: EventSource,
    id: String?,
    type: String?,
    data: String,
  ) {
  }

  /**

        hasModifier(KtTokens.OPEN_KEYWORD) -> {
            if (this is KtCallableDeclaration && !hasBody()) {
                val parentDeclaration = this.getElementParentDeclaration()
                if (parentDeclaration is KtClass && parentDeclaration.isInterface()) {
                    Modality.ABSTRACT
                } else {
                    Modality.OPEN
                }
            }

```Python
with open("file.txt") as file:
    file.read()
```

In neueren Versionen von Python gibt es auch einen **asynchronen Kontextmanager**. Sie würden ihn mit `async with` verwenden:

```Python
async with lifespan(app):
    await do_stuff()
```

@SuppressSignatureCheck
sealed class ConnectionEvent {
  abstract val timestampNs: Long
  open val connection: Connection?
    get() = null

  /** Returns if the event closes this event, or null if this is no open event. */
  open fun closes(event: ConnectionEvent): Boolean? = null

  val name: String
    get() = javaClass.simpleName

  data class ConnectStart(

    }
  }

  /**
   * Returns true if this stream is open. A stream is open until either:
   *
   *  * A `SYN_RESET` frame abnormally terminates the stream.
   *  * Both input and output streams have transmitted all data and headers.
   *
   * Note that the input stream may continue to yield data even after a stream reports itself as
   * not open. This is because input data is buffered.
   */
  val isOpen: Boolean

import java.net.ServerSocket
import javax.net.ServerSocketFactory

/**
 * A [ServerSocketFactory] that delegates calls. Sockets can be configured after creation by
 * overriding [.configureServerSocket].
 */
open class DelegatingServerSocketFactory(private val delegate: ServerSocketFactory) : ServerSocketFactory() {
  @Throws(IOException::class)
  override fun createServerSocket(): ServerSocket {

/**
 * Manages reuse of HTTP and HTTP/2 connections for reduced network latency. HTTP requests that
 * share the same [Address] may share a [Connection]. This class implements the policy
 * of which connections to keep open for future use.
 *
 * @constructor Create a new connection pool with tuning parameters appropriate for a single-user
 * application. The tuning parameters in this pool are subject to change in future OkHttp releases.