### EventListener.Factory

In the preceding example we used a field, `callStartNanos`, to track the elapsed time of each event. This is handy, but it won’t work if multiple calls are executing concurrently. To accommodate this, use a `Factory` to create a new `EventListener` instance for each `Call`. This allows each listener to keep call-specific state.

 * All comments are ignored.
 *
 * Regular lines contain fields separated by semicolons.
 *
 * The first element on each line is a single hex code point (like 0041) or a hex code point range
 * (like 0030..0039).
 *
 * The second element on each line is a mapping type, like `valid` or `mapped`.
 *
 * For lines that contain a mapping target, the next thing is a sequence of hex code points (like

#### Http2Connection

This lock guards internal state of each connection. This lock is never held for blocking operations. That means that we acquire the lock, read or write a few fields and release the lock. No I/O and no application-layer callbacks.

#### Http2Stream

      var unexpectedValues = false

      // Parse each header.
      for (i in 0 until responseHeaders.size) {
        if (!responseHeaders.name(i).equals(HEADER_WEB_SOCKET_EXTENSION, ignoreCase = true)) {
          continue // Not a header we're interested in.
        }
        val header = responseHeaders.value(i)

        // Parse each extension.
        var pos = 0
        while (pos < header.length) {

 * decide not to by returning -1L.
 *
 * Task Queues
 * -----------
 *
 * Tasks are bound to the [TaskQueue] they are scheduled in. Each queue is sequential and the tasks
 * within it never execute concurrently. It is an error to use a task in multiple queues.
 */
abstract class Task(
  val name: String,
  val cancelable: Boolean = true,
) {

  /** The body of this POST request. This may be truncated. */
  val body: Buffer,
  /**
   * The index of this request on its HTTP connection. Since a single HTTP connection may serve
   * multiple requests, each request is assigned its own sequence number.
   */
  val sequenceNumber: Int,
  socket: Socket,
  /**
   * The failure MockWebServer recorded when attempting to decode this request. If, for example,

import okhttp3.internal.concurrent.TaskRunner
import okhttp3.internal.connection.RoutePlanner.ConnectResult
import okhttp3.internal.connection.RoutePlanner.Plan
import okhttp3.internal.okHttpName

/**
 * Speculatively connects to each IP address of a target address, returning as soon as one of them
 * connects successfully. This kicks off new attempts every 250 ms until a connect succeeds.
 */
internal class FastFallbackExchangeFinder(

      return SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss 'GMT'", Locale.US).apply {
        isLenient = false
        timeZone = UTC
      }
    }
  }

/** If we fail to parse a date in a non-standard format, try each of these formats in sequence. */
private val BROWSER_COMPATIBLE_DATE_FORMAT_STRINGS =
  arrayOf(
    // HTTP formats required by RFC2616 but with any timezone:
    // RFC 822, updated by RFC 1123 with any TZ.

import okhttp3.internal.assertNotHeld
import okhttp3.internal.okHttpName

/**
 * A set of tasks that are executed in sequential order.
 *
 * Work within queues is not concurrent. This is equivalent to each queue having a dedicated thread
 * for its work; in practice a set of queues may share a set of threads to save resources.
 */
class TaskQueue internal constructor(
  internal val taskRunner: TaskRunner,

  }
  return commaFound
}

private fun Buffer.startsWith(prefix: Byte): Boolean = !exhausted() && this[0] == prefix

/**
 * Reads a double-quoted string, unescaping quoted pairs like `\"` to the 2nd character in each
 * sequence. Returns the unescaped string, or null if the buffer isn't prefixed with a
 * double-quoted string.
 */
@Throws(EOFException::class)
private fun Buffer.readQuotedString(): String? {