*/
abstract class Task(
  val name: String,
  val cancelable: Boolean = true,
) {
  // Guarded by the TaskRunner.
  internal var queue: TaskQueue? = null

  /** Undefined unless this is in [TaskQueue.futureTasks]. */
  internal var nextExecuteNanoTime = -1L

  /** Returns the delay in nanoseconds until the next execution, or -1L to not reschedule. */
  abstract fun runOnce(): Long

  private val codec: Codec<T>,
  /** True if the default value should be used if this value is absent during decoding. */
  val isOptional: Boolean = false,
  /** The value to return if this value is absent. Undefined unless this is optional. */
  val defaultValue: T? = null,
  /** True to set the encoded or decoded value as the type hint for the current SEQUENCE. */
  private val typeHint: Boolean = false,
) : DerAdapter<T> {
  init {

      max*)
        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
        # shellcheck disable=SC2039,SC3045
        MAX_FD=$( ulimit -H -n ) ||
            warn "Could not query maximum file descriptor limit"
    esac
    case $MAX_FD in  #(
      '' | soft) :;; #(
      *)
        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.

    get() = "chunked".equals(header("Transfer-Encoding"), ignoreCase = true)

  /**
   * Received trailers. Null unless the response body uses chunked transfer-encoding and includes
   * trailers. Undefined until the end of the response body.
   */
  private var trailers: Headers? = null

  /** Returns true if this connection is closed. */
  val isClosed: Boolean
    get() = state == STATE_CLOSED

  var count = 0
  while (!exhausted() && this[0] == b) {
    count++
    readByte()
  }
  return count
}

/**
 * Returns the index of the next non-whitespace character in this. Result is undefined if input
 * contains newline characters.
 */
internal fun String.indexOfNonWhitespace(startIndex: Int = 0): Int {
  for (i in startIndex until length) {
    val c = this[i]
    if (c != ' ' && c != '\t') {

  fun writePong(payload: ByteString) {
    writeControlFrame(OPCODE_CONTROL_PONG, payload)
  }

  /**
   * Send a close frame with optional code and reason.
   *
   * @param code Status code as defined by
   *     [Section 7.4 of RFC 6455](http://tools.ietf.org/html/rfc6455#section-7.4) or `0`.
   * @param reason Reason for shutting down or `null`.
   */
  @Throws(IOException::class)
  fun writeClose(
    code: Int,

   * This returns true if a graceful shutdown was initiated by this call. It returns false if
   * a graceful shutdown was already underway or if the web socket is already closed or canceled.
   *
   * @param code Status code as defined by
   *     [Section 7.4 of RFC 6455](http://tools.ietf.org/html/rfc6455#section-7.4).
   * @param reason Reason for shutting down, no longer than 123 bytes of UTF-8 encoded data (**not** characters) or null.

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

      return null // If we already failed with these credentials, don't retry.
     }
    ```

    You may also skip the retry when you’ve hit an application-defined attempt limit:

    ```kotlin
    if (response.responseCount >= 3) {
      return null // If we've failed 3 times, give up.
    }
    ```

    This above code relies on this `responseCount` extension val:

    val receiveBuffer = Buffer()

    /** Buffer with readable data. Guarded by Http2Stream.this. */
    val readBuffer = Buffer()

    /**
     * Received trailers. Null unless the server has provided trailers. Undefined until the stream
     * is exhausted. Guarded by Http2Stream.this.
     */
    var trailers: Headers? = null

    /** True if the caller has closed this stream. */
    internal var closed: Boolean = false