The upcoming Android Studio runs in a JVM but has classes from Android and that confused OkHttp!

 *  Fix: Include the header `Accept: text/event-stream` for SSE calls. This header is not added if
    the request already contains an `Accept` header.

 *  Fix: Don't crash with a `NullPointerException` if a server sends a close while we're sending a
    ping. OkHttp had a race condition bug.


## Version 4.6.0

_2020-04-28_

    val derReader = DerReader(buffer)

    derReader.read("test") { header ->
      assertThat(header.tag).isEqualTo(2L)
      assertThat(header.tagClass).isEqualTo(DerHeader.TAG_CLASS_CONTEXT_SPECIFIC)
      assertThat(header.length).isEqualTo(7L)

      derReader.read("test") { header ->
        assertThat(header.tag).isEqualTo(3L)
        assertThat(header.tagClass).isEqualTo(DerHeader.TAG_CLASS_APPLICATION)

      // Read the header.
      val header = Buffer()
      fileOperator.read(0, header, FILE_HEADER_SIZE)
      val prefix = header.readByteString(PREFIX_CLEAN.size.toLong())
      if (prefix != PREFIX_CLEAN) throw IOException("unreadable cache file")
      val upstreamSize = header.readLong()
      val metadataSize = header.readLong()

      // Read the metadata.

  for (i in 0 until length) {
    val c = this[i]
    // The WHATWG Host parsing rules accepts some character codes which are invalid by
    // definition for OkHttp's host header checks (and the WHATWG Host syntax definition). Here
    // we rule out characters that would cause problems in host headers.
    if (c <= '\u001f' || c >= '\u007f') {
      return true
    }

 * the response, the client will issue a conditional `GET`. The server will then send either
 * the updated response if it has changed, or a short 'not modified' response if the client's copy
 * is still valid. Such responses increment both the network count and hit count.
 *
 * The best way to improve the cache hit rate is by configuring the web server to return cacheable

          }
          line[0] == ':' -> {
            // Work around empty header names and header names that start with a colon (created by old
            // broken SPDY versions of the response cache).
            addLenient("", line.substring(1)) // Empty header name.
          }
          else -> {
            // No header name.
            addLenient("", line)
          }
        }
      }

        headers = Headers.Builder()
      }

    /**
     * Adds [header] as an HTTP header. For well-formed HTTP [header] should contain a name followed
     * by a colon and a value.
     */
    fun addHeader(header: String) =
      apply {
        headers.add(header)
      }

    /**
     * Adds a new header with the name and value. This may be used to add multiple headers with the
     * same name.

        this.handshake = handshake
      }

    /**
     * Sets the header named [name] to [value]. If this request already has any headers
     * with that name, they are all replaced.
     */
    open fun header(
      name: String,
      value: String,
    ) = commonHeader(name, value)

    /**
     * Adds a header with [name] to [value]. Prefer this method for multiply-valued

  private var state = STATE_IDLE
  private val headersReader = HeadersReader(source)

  private val Response.isChunked: Boolean
    get() = "chunked".equals(header("Transfer-Encoding"), ignoreCase = true)

  private val Request.isChunked: Boolean
    get() = "chunked".equals(header("Transfer-Encoding"), ignoreCase = true)

  /**
   * Received trailers. Null unless the response body uses chunked transfer-encoding and includes

  val clientTestRule = OkHttpClientTestRule()
  private lateinit var server: MockWebServer
  private var client = clientTestRule.newClient()

  @BeforeEach
  fun setUp(server: MockWebServer) {
    this.server = server
  }

  @Test
  fun testNetscapeResponse() {
    val cookieManager = CookieManager(null, CookiePolicy.ACCEPT_ORIGINAL_SERVER)
    client =
      client.newBuilder()