// 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.

    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.

    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)

            override fun close() {
              closed.set(true)
              super.close()
            }
          }.buffer()
        }
      }
    val reader = body.charStream()
    assertThat(reader.read()).isEqualTo('h'.code)
    reader.close()
    assertThat(closed.get()).isTrue()
  }

  @Test
  fun sourceSeesBom() {
    val body = "efbbbf68656c6c6f".decodeHex().toResponseBody()

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
@file:Suppress("INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")

package okhttp3.logging

import java.io.IOException
import java.nio.charset.Charset
import java.util.TreeSet
import java.util.concurrent.TimeUnit
import okhttp3.Headers

  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
    }

        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.

      override fun matches(header: DerHeader): Boolean = true

      override fun fromDer(reader: DerReader): AnyValue {
        reader.read("ANY") { header ->
          val bytes = reader.readUnknown()
          return AnyValue(
            tagClass = header.tagClass,
            tag = header.tag,
            constructed = header.constructed,
            length = header.length,
            bytes = bytes,

          }
          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)
          }
        }
      }

    connection.setRequestProperty("Accept-Language", "en-US")
    val inputStream = connection.inputStream
    val reader = BufferedReader(InputStreamReader(inputStream, StandardCharsets.UTF_8))
    assertThat(connection.getResponseCode()).isEqualTo(HttpURLConnection.HTTP_OK)
    assertThat(reader.readLine()).isEqualTo("hello world")
    val request = server.takeRequest()
    assertThat(request.requestLine).isEqualTo("GET / HTTP/1.1")