this because it only occurs if you have proxy configured and you share a connection pool among
    multiple `OkHttpClient` instances.

    This particularly-subtle bug was caused by us assigning each `OkHttpClient` instance its own
    `NullProxySelector` when an explicit proxy is configured. But we don't share connections when
    the proxy selectors are different. Ugh!

These are the primary classes involved with establishing, sharing, and terminating connections:

 * **RealConnectionPool** manages reuse of HTTP and HTTP/2 connections for reduced latency. Every OkHttpClient has one, and its lifetime spans the lifetime of the OkHttpClient.

 * limitations under the License.
 */
package okhttp3.recipes.kt

import java.io.IOException
import okhttp3.CertificatePinner
import okhttp3.OkHttpClient
import okhttp3.Request

class CertificatePinning {
  private val client =
    OkHttpClient
      .Builder()
      .certificatePinner(
        CertificatePinner
          .Builder()

pragmatic caching behaviour, following common real-world browser like Firefox/Chrome and 
server behaviour when ambiguous.

# Basic Usage

```kotlin
  private val client: OkHttpClient = OkHttpClient.Builder()
      .cache(Cache(
          directory = File(application.cacheDir, "http_cache"),
          // $0.05 worth of phone storage in 2020
          maxSize = 50L * 1024L * 1024L // 50 MiB
      ))

gradlePlugin-shadow = "com.gradleup.shadow:shadow-gradle-plugin:9.1.0"
gradlePlugin-spotless = "com.diffplug.spotless:spotless-plugin-gradle:7.2.1"
hamcrestLibrary = "org.hamcrest:hamcrest-library:3.0"
httpClient5 = "org.apache.httpcomponents.client5:httpclient5:5.5"
#noinspection NewerVersionAvailable
jettyClient = "org.eclipse.jetty:jetty-client:9.4.58.v20250814"
jnr-unixsocket = "com.github.jnr:jnr-unixsocket:0.38.23"
jsoup = "org.jsoup:jsoup:1.21.2"

```kotlin
testImplementation("com.squareup.okhttp3:okhttp-dnsoverhttps:5.1.0")
```

### Usage

```
  val appCache = Cache(File("cacheDir", "okhttpcache"), 10 * 1024 * 1024)
  val bootstrapClient = OkHttpClient.Builder().cache(appCache).build()

  val dns = DnsOverHttps.Builder().client(bootstrapClient)
    .url("https://dns.google/dns-query".toHttpUrl())

public final class UploadProgress {
  private static final String IMGUR_CLIENT_ID = "9199fdef135c122";
  private static final MediaType MEDIA_TYPE_PNG = MediaType.get("image/png");

  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    // Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image
    final ProgressListener progressListener = new ProgressListener() {

            final String owner = (String) responseData.getMetaDataMap().get(FtpClient.FTP_FILE_USER);
            if (owner != null) {
                roleTypeList.add(systemHelper.getSearchRoleByUser(owner));
            }
            final String group = (String) responseData.getMetaDataMap().get(FtpClient.FTP_FILE_GROUP);
            if (group != null) {

first. Fast fallback gives IPv6 connections a 250 ms head start so IPv6 is preferred on networks
where it's available.

To opt-in, configure your `OkHttpClient.Builder`:


```
OkHttpClient client = new OkHttpClient.Builder()
    .fastFallback(true)
    .build();
```

 *  New: Change the build from Kotlin-JVM to Kotlin-multiplatform (which includes JVM). Both

    OkHttp 2 the built-in disk cache is the only supported response cache.

 *  **HttpResponseCache has been renamed to Cache.** Install it with
    `OkHttpClient.setCache(...)` instead of `OkHttpClient.setResponseCache(...)`.

 *  **OkAuthenticator has been replaced with Authenticator.** This new
    authenticator has access to the full incoming response and can respond with