* [system DNS service][SYSTEM], which is the default. Some applications may provide their own
 * implementation to use a different DNS server, to prefer IPv6 addresses, to prefer IPv4 addresses,
 * or to force a specific known IP address.
 *
 * Implementations of this interface must be safe for concurrent use.
 */
fun interface Dns {
  /**

    if (!string.regionMatches(pos, PREFIX_STRING, 0, 4, ignoreCase = true)) {
      result.writeUtf8(string, pos, limit)
      return true
    }

    var pos = pos + 4 // 'xn--'.size.

    // We'd prefer to operate directly on `result` but it doesn't offer insertCodePoint(), only
    // appendCodePoint(). The Punycode algorithm processes code points in increasing code-point
    // order, not in increasing index order.

## Version 4.7.0

_2020-05-17_

 *  New: `HandshakeCertificates.Builder.addInsecureHost()` makes it easy to turn off security in
    private development environments that only carry test data. Prefer this over creating an
    all-trusting `TrustManager` because only hosts on the allowlist are insecure. From
    [our DevServer sample][dev_server]:

    ```kotlin

      /**
       * For whatever reason our BouncyCastle provider doesn't work with ECDSA keys. Just configure it
       * to use RSA-2048 instead.
       *
       * (We otherwise prefer ECDSA because it's faster.)
       */
      private val localhostHandshakeCertificatesWithRsa2048: HandshakeCertificates by lazy {
        val heldCertificate =
          HeldCertificate.Builder()

      init(null, arrayOf<TrustManager>(trustManager), null)
    }.socketFactory
  }

  companion object {
    val isSupported: Boolean =
      try {
        // Trigger an early exception over a fatal error, prefer a RuntimeException over Error.
        Class.forName("org.conscrypt.Conscrypt\$Version", false, javaClass.classLoader)

        when {
          // Bump this version if we ever have a binary incompatibility

  }

  @JvmStatic
  val windows: Boolean
    get() = System.getProperty("os.name", "?").startsWith("Windows")

  /**
   * Make assertions about the suppressed exceptions on this. Prefer this over making direct calls
   * so tests pass on GraalVM, where suppressed exceptions are silently discarded.
   *
   * https://github.com/oracle/graal/issues/3008
   */
  @JvmStatic

      } else {
        fileSystem.atomicMove(journalFileBackup, journalFile)
      }
    }

    civilizedFileSystem = fileSystem.isCivilized(journalFileBackup)

    // Prefer to pick up where we left off.
    if (fileSystem.exists(journalFile)) {
      try {
        readJournal()
        processJournal()
        initialized = true
        return

  }

  /**
   * When the server returns a full response body we will store it and return it regardless of what
   * its Last-Modified date is. This behavior was different prior to OkHttp 3.5 when we would prefer
   * the response with the later Last-Modified date.
   *
   * https://github.com/square/okhttp/issues/2886
   */
  @Test
  fun serverReturnsDocumentOlderThanCache() {
    server.enqueue(

 *
 * This implementation delegates everything to [okhttp3.java.net.cookiejar.JavaNetCookieJar], which
 * conforms to the package-naming limitations of JPMS.
 *
 * Callers should prefer to use [okhttp3.java.net.cookiejar.JavaNetCookieJar] directly.
 */
class JavaNetCookieJar private constructor(
  delegate: okhttp3.java.net.cookiejar.JavaNetCookieJar,
) : CookieJar by delegate {

 * connection is typically faster than establishing a new one.
 *
 * When a single logical call requires multiple streams due to redirects or authorization
 * challenges, we prefer to use the same physical connection for all streams in the sequence. There
 * are potential performance and behavior consequences to this preference. To support this feature,