require(type is KtFe10Type)
        return TypeUtils.isNullableType(type.fe10Type)
    }

    override fun isDenotable(type: KtType): Boolean {
        require(type is KtFe10Type)
        val kotlinType = type.fe10Type
        return kotlinType.isDenotable()
    }

    override fun isArrayOrPrimitiveArray(type: KtType): Boolean {
        require(type is KtFe10Type)

    }

    private fun isSubClassOf(subClass: KtClassOrObjectSymbol, superClass: KtClassOrObjectSymbol, allowIndirectSubtyping: Boolean): Boolean {
        require(subClass is KtFirSymbol<*>)
        require(superClass is KtFirSymbol<*>)

        if (subClass == superClass) return false
        return isSubClassOf(
            subClass = subClass.firSymbol.fir as FirClass,

    override fun getInheritorsOfSealedClass(
        classSymbol: KtNamedClassOrObjectSymbol
    ): List<KtNamedClassOrObjectSymbol> {
        require(classSymbol.modality == Modality.SEALED)
        require(classSymbol is KtFirNamedClassOrObjectSymbol)

        val inheritorClassIds = classSymbol.firSymbol.fir.getSealedClassInheritors(analysisSession.useSiteSession)

      apply {
        val maxAgeSeconds = maxAge.inWholeSeconds
        require(maxAgeSeconds >= 0) { "maxAge < 0: $maxAgeSeconds" }
        this.maxAgeSeconds = maxAgeSeconds.commonClampToInt()
      }

    fun maxStale(maxStale: Duration) =
      apply {
        val maxStaleSeconds = maxStale.inWholeSeconds
        require(maxStaleSeconds >= 0) { "maxStale < 0: $maxStaleSeconds" }

  return null
}

internal fun Headers.Builder.commonBuild(): Headers = Headers(namesAndValues.toTypedArray())

internal fun headersCheckName(name: String) {
  require(name.isNotEmpty()) { "name is empty" }
  for (i in name.indices) {
    val c = name[i]
    require(c in '\u0021'..'\u007e') {
      "Unexpected char 0x${c.charCode()} at $i in header name: $name"
    }
  }
}

internal fun headersCheckValue(

    flags: Int,
  ) {
    if (type != TYPE_WINDOW_UPDATE && logger.isLoggable(FINE)) {
      logger.fine(frameLog(false, streamId, length, type, flags))
    }
    require(length <= maxFrameSize) { "FRAME_SIZE_ERROR length > $maxFrameSize: $length" }
    require(streamId and 0x80000000.toInt() == 0) { "reserved bit set: $streamId" }
    sink.writeMedium(length)
    sink.writeByte(type and 0xff)
    sink.writeByte(flags and 0xff)

        ) == null
    }

    override fun isArrayOrPrimitiveArray(type: KtType): Boolean {
        require(type is KtFirType)
        return type.coneType.isArrayOrPrimitiveArray
    }

    override fun isNestedArray(type: KtType): Boolean {
        if (!isArrayOrPrimitiveArray(type)) return false
        require(type is KtFirType)
        return type.coneType.arrayElementType()?.isArrayOrPrimitiveArray == true
    }

  ) : SerialTask {
    override fun start() {
      taskRunner.assertThreadHoldsLock()
      require(currentTask == this)
      activeThreads++

      tasksExecutor.execute {
        taskRunner.assertThreadDoesntHoldLock()
        require(currentTask == this)
        try {
          runnable.run()
          require(currentTask == this) { "unexpected current task: $currentTask" }
        } finally {

  val millis = unit.toMillis(duration)
  require(millis <= Integer.MAX_VALUE) { "$name too large" }
  require(millis != 0L || duration <= 0L) { "$name too small" }
  return millis.toInt()
}

internal fun checkDuration(
  name: String,
  duration: Duration,
): Int {
  check(!duration.isNegative()) { "$name < 0" }
  val millis = duration.inWholeMilliseconds
  require(millis <= Integer.MAX_VALUE) { "$name too large" }

        if (currentPart == this) {
          currentPart = null
        }
      }

      override fun read(
        sink: Buffer,
        byteCount: Long,
      ): Long {
        require(byteCount >= 0L) { "byteCount < 0: $byteCount" }
        check(currentPart == this) { "closed" }

        source.timeout().intersectWith(timeout) {