* limits, this call may be executed well before processing the request is able to begin.
   *
   * This will be invoked only once for a single [Call]. Retries of different routes or redirects
   * will be handled within the boundaries of a single [callStart] and [callEnd]/[callFailed] pair.
   */
  open fun callStart(call: Call) {
  }

  /**
   * Invoked prior to a proxy selection.
   *

  val credential: String?,
  val scheme: String?,
) : Authenticator {
  val responses = mutableListOf<Response>()
  val routes = mutableListOf<Route>()

  fun onlyResponse() = responses.single()

  fun onlyRoute() = routes.single()

  @Throws(IOException::class)
  override fun authenticate(
    route: Route?,
    response: Response,
  ): Request? {
    if (route == null) throw NullPointerException("route == null")

 */
package okhttp3.internal.http2.hpackjson

import okhttp3.internal.http2.Header
import okio.ByteString

/**
 * Representation of an individual case (set of headers and wire format). There are many cases for a
 * single story.  This class is used reflectively with Moshi to parse stories.
 */
data class Case(
  val seqno: Int = 0,
  val wire: ByteString? = null,
  val headers: List<Map<String, String>>,
) : Cloneable {

    val certificates =
      certificateFactory
        .generateCertificates(
          Buffer().writeUtf8(this).inputStream(),
        )

    return certificates.single() as X509Certificate
  } catch (nsee: NoSuchElementException) {
    throw IllegalArgumentException("failed to decode certificate", nsee)
  } catch (iae: IllegalArgumentException) {

      code: Int,
      reason: String,
    )
  }

  /**
   * Process the next protocol frame.
   *
   *  * If it is a control frame this will result in a single call to [FrameCallback].
   *  * If it is a message frame this will result in a single call to [FrameCallback.onReadMessage].
   *    If the message spans multiple frames, each interleaved control frame will result in a
   *    corresponding call to [FrameCallback].

          parameter.groups[3]!!.value
        }
        token.startsWith("'") && token.endsWith("'") && token.length > 2 -> {
          // If the token is 'single-quoted' it's invalid! But we're lenient and strip the quotes.
          token.substring(1, token.length - 1)
        }
        else -> token
      }

    parameterNamesAndValues += name

      payload.writeByte('0'.code)
    }
    serverWriter.writeMessageFrame(OPCODE_BINARY, payload.snapshot())

    // Write directly to the unbuffered sink. This ensures it will become single frame.
    assertData("827e") // 'e' == 4-byte follow-up length.
    assertData(format("%04X", payload.completeSegmentByteCount()))
    assertData(payload.readByteString())
  }

A single HTTP call may require follow-up requests to be made to handle authentication challenges, redirects, and HTTP-layer timeouts. In such cases multiple connections, requests, and responses may be attempted. Follow-ups are another reason a single call may trigger multiple events of the same type.

      Collections.unmodifiableList(cookies)
    } else {
      emptyList()
    }
  }

  /**
   * Convert a request header to OkHttp's cookies via [HttpCookie]. That extra step handles
   * multiple cookies in a single request header, which [Cookie.parse] doesn't support.
   */
  private fun decodeHeaderAsJavaNetCookies(
    url: HttpUrl,
    header: String,
  ): List<Cookie> {
    val result = mutableListOf<Cookie>()

    fun onEvent(
      id: String?,
      type: String?,
      data: String,
    )

    fun onRetryChange(timeMs: Long)
  }

  /**
   * Process the next event. This will result in a single call to [Callback.onEvent] *unless* the
   * data section was empty. Any number of calls to [Callback.onRetryChange] may occur while
   * processing an event.
   *
   * @return false when EOF is reached
   */