fileOperator!!.read(FILE_HEADER_SIZE + sourcePos, sink, bytesToRead)
        sourcePos += bytesToRead
        return bytesToRead
      }

      // Read from upstream. This always reads a full buffer: that might be more than what the
      // current call to Source.read() has requested.
      try {
        val upstreamBytesRead = upstream!!.read(upstreamBuffer, bufferMaxSize)

      assertSetEquals(
        "seqno=$testCase.seqno",
        testCase.headersList,
        hpackReader.getAndResetHeaderList(),
      )
    }
  }

  companion object {
    /**
     * Reads all stories in the folders provided, asserts if no story found.
     */
    @JvmStatic
    protected fun createStories(interopTests: Array<String>): List<Any> {
      if (interopTests.isEmpty()) return listOf<Any>(Story.MISSING)

   * [reader]. For example, if the reader's peeked tag isn't readable by this adapter, it may return
   * a default value.
   *
   * If this does read a value, it starts with the tag and length, and reads an entire value,
   * including any potential composed values.
   *
   * If there's nothing to read and no default value, this will throw an exception.
   */
  fun fromDer(reader: DerReader): T

_2019-10-06_

 *  Fix: When closing a canceled HTTP/2 stream, don't send the `END_STREAM` flag. This could cause
    the server to incorrectly interpret the stream as having completed normally. This is most useful
    when a request body needs to cancel its own call.


## Version 4.2.1

_2019-10-02_

 *  Fix: In 4.1.0 we introduced a performance regression that prevented connections from being

private fun BufferedSource.skipRestOfLine() {
  when (val newline = indexOf('\n'.code.toByte())) {
    -1L -> skip(buffer.size) // Exhaust this source.
    else -> skip(newline + 1)
  }
}

/**
 * Reads lines from `IdnaMappingTable.txt`.
 *
 * Comment lines are either blank or start with a `#` character. Lines may also end with a comment.
 * All comments are ignored.
 *

    URLConnection.setDefaultRequestProperty("X-testSetDefaultRequestProperty", "A")
    assertThat(URLConnection.getDefaultRequestProperty("X-setDefaultRequestProperty")).isNull()
  }

  /**
   * Reads `count` characters from the stream. If the stream is exhausted before `count`
   * characters can be read, the remaining characters are returned and the stream is closed.
   */
  private fun readAscii(

Framing rules make it impractical to implement http/2 correctly on a single blocking thread. The flow-control features introduce feedback between reads and writes, requiring writes to acknowledge reads and reads to throttle writes.

In OkHttp we expose a blocking API over a framed protocol. This document explains the code and policy that makes that work.

### Threads

#### Application's calling thread

   * up the necessary in-memory cache information.
   *
   * The initialization time may vary depending on the journal file size and the current actual
   * cache size. The application needs to be aware of calling this function during the
   * initialization phase and preferably in a background worker thread.
   *
   * Note that if the application chooses to not call this method to initialize the cache. By

  /** Read a single line counted against the header size limit. */
  fun readLine(): String {
    val line = source.readUtf8LineStrict(headerLimit)
    headerLimit -= line.length.toLong()
    return line
  }

  /** Reads headers or trailers. */
  fun readHeaders(): Headers {
    val result = Headers.Builder()
    while (true) {
      val line = readLine()
      if (line.isEmpty()) break
      result.addLenient(line)
    }

    result = 31 * result + defaultValue.hashCode()
    result = 31 * result + (if (typeHint) 1 else 0)
    return result
  }

  override fun toString(): String = "$name [$tagClass/$tag]"

  /** Reads and writes values without knowledge of the enclosing tag, length, or defaults. */
  interface Codec<T> {
    fun decode(reader: DerReader): T

    fun encode(
      writer: DerWriter,
      value: T,
    )