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. */

        serveFile(stream, file)
      } else {
        send404(stream, path)
      }
    } catch (e: IOException) {
      Platform.get().log("Failure serving Http2Stream: " + e.message, Platform.INFO, null)
    }
  }

  private fun send404(
    stream: Http2Stream,
    path: String,
  ) {
    val responseHeaders =
      listOf(
        Header(":status", "404"),
        Header(":version", "HTTP/1.1"),

      val streamsCopy: Array<Http2Stream>
      withLock {
        streamsCopy = streams.values.toTypedArray()
        isShutdown = true
      }

      // Fail all streams created after the last good stream ID.
      for (http2Stream in streamsCopy) {
        if (http2Stream.id > lastGoodStreamId && http2Stream.isLocallyInitiated) {
          http2Stream.receiveRstStream(REFUSED_STREAM)

import okhttp3.internal.http.HttpMethod
import okhttp3.internal.http2.ErrorCode
import okhttp3.internal.http2.Header
import okhttp3.internal.http2.Http2Connection
import okhttp3.internal.http2.Http2Stream
import okhttp3.internal.immutableListOf
import okhttp3.internal.platform.Platform
import okhttp3.internal.threadFactory
import okhttp3.internal.toImmutableList
import okhttp3.internal.ws.RealWebSocket

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

  client: OkHttpClient,
  override val carrier: Carrier,
  private val chain: RealInterceptorChain,
  private val http2Connection: Http2Connection,
) : ExchangeCodec {
  @Volatile private var stream: Http2Stream? = null

  private val protocol: Protocol =
    if (Protocol.H2_PRIOR_KNOWLEDGE in client.protocols) {
      Protocol.H2_PRIOR_KNOWLEDGE
    } else {
      Protocol.HTTP_2
    }

  @Volatile

    val maxConcurrentStreams = AtomicInteger()
    val listener: Http2Connection.Listener =
      object : Http2Connection.Listener() {
        override fun onStream(stream: Http2Stream): Unit = throw AssertionError()

        override fun onSettings(
          connection: Http2Connection,
          settings: Settings,
        ) {