long callId = nextCallId.getAndIncrement();
      System.out.printf("%04d %s%n", callId, call.request().url());
      return new PrintingEventListener(callId, System.nanoTime());
    }
  };

  final long callId;
  final long callStartNanos;

  public PrintingEventListener(long callId, long callStartNanos) {
    this.callId = callId;
    this.callStartNanos = callStartNanos;
  }

import okio.Options
import okio.Source
import okio.Timeout
import okio.buffer

/**
 * Reads a stream of [RFC 2046][rfc_2046] multipart body parts. Callers read parts one-at-a-time
 * until [nextPart] returns null. After calling [nextPart] any preceding parts should not be read.
 *
 * Typical use loops over the parts in sequence:
 *
 * ```kotlin
 * val response: Response = call.execute()
 * val multipartReader = MultipartReader(response.body!!)

 * deterministic.
 *
 * This class ensures that at most one thread is running at a time. This is initially the JUnit test
 * thread, which yields its execution privilege while calling [runTasks], [runNextTask], or
 * [advanceUntil]. These functions don't return until the task threads are all idle.
 *
 * Task threads release their execution privilege in these ways:
 *

    }

    if (queue.futureTasks.isNotEmpty()) {
      readyQueues.add(queue)
    }
  }

  /**
   * Returns an immediately-executable task for the calling thread to execute, sleeping as necessary
   * until one is ready. If there are no ready queues, or if other threads have everything under

 *
 * Both this class and [Response] implement [Closeable]. Closing a response simply
 * closes its response body. If you invoke [Call.execute] or implement [Callback.onResponse] you
 * must close this body by calling any of the following methods:
 *
 * * `Response.close()`
 * * `Response.body().close()`
 * * `Response.body().source().close()`
 * * `Response.body().charStream().close()`
 * * `Response.body().byteStream().close()`

        this.url = url
      }

    /**
     * Sets the URL target of this request.
     *
     * @throws IllegalArgumentException if [url] is not a valid HTTP or HTTPS URL. Avoid this
     *     exception by calling [HttpUrl.parse]; it returns null for invalid URLs.
     */
    open fun url(url: String): Builder {
      return url(canonicalUrl(url).toHttpUrl())
    }

    /**
     * Sets the URL target of this request.

HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
logging.setLevel(Level.BASIC);
OkHttpClient client = new OkHttpClient.Builder()
  .addInterceptor(logging)
  .build();
```

You can change the log level at any time by calling `setLevel()`.

To log to a custom location, pass a `Logger` instance to the constructor.
```java
HttpLoggingInterceptor logging = new HttpLoggingInterceptor(new Logger() {
  @Override public void log(String message) {

 *  The challenge's scheme and realm are now non-null. If you are calling
    `new Challenge(scheme, realm)` you must provide non-null values. These were
    never null in challenges created by OkHttp, but could have been null in
    application code that creates challenges.

 *  New: The `TlsVersion` of a `Handshake` is now non-null. If you are calling
    `Handshake.get()` with a null TLS version, you must instead now provide a

    parts.nextPart()!!
    val partMno = parts.nextPart()!!
    assertThat(partMno.body.readUtf8()).isEqualTo("mnop")

    assertThat(parts.nextPart()).isNull()
  }

  @Test fun `cannot read part after calling nextPart`() {
    val multipart =
      """
      |--simple boundary
      |
      |abcd
      |efgh
      |ijkl
      |--simple boundary
      |
      |mnop
      |--simple boundary--

In OkHttp we expose a blocking API over a framed protocol. This document explains the code and policy that makes that work.

### Threads

#### Application's calling thread