public String getUserId() {
        return username;
    }

    /**
     * Returns a string representation of this credential.
     *
     * @return A string representation containing the username in braces
     */
    @Override
    public String toString() {
        return "{" + username + "}";
    }

      builder.append(args[i++]);
      templateStart = placeholderStart + 2;
    }
    builder.append(template.substring(templateStart));

    // if we run out of placeholders, append the extra args in square braces
    if (i < args.length) {
      builder.append(" [");
      builder.append(args[i++]);
      while (i < args.length) {
        builder.append(", ");
        builder.append(args[i++]);
      }

 */
internal fun String.toCanonicalHost(): String? {
  val host: String = this

  // If the input contains a :, it’s an IPv6 address.
  if (":" in host) {
    // If the input is encased in square braces "[...]", drop 'em.
    val inetAddressByteArray =
      (
        if (host.startsWith("[") && host.endsWith("]")) {
          decodeIpv6(host, 1, host.length - 1)
        } else {

   *     argument. These are matched by position - the first {@code %s} gets {@code
   *     errorMessageArgs[0]}, etc. Unmatched arguments will be appended to the formatted message in
   *     square braces. Unmatched placeholders will be left as-is.
   * @param errorMessageArgs the arguments to be substituted into the message template. Arguments
   *     are converted to strings using {@link String#valueOf(Object)}.

        '^'.code,
        '`'.code,
        '{'.code,
        '|'.code,
        '}'.code,
      ).test(UrlComponentEncodingTester.Component.HOST)
  }

  @Test
  fun hostIpv6() {
    // Square braces are absent from host()...
    assertThat(parse("http://[::1]/").host).isEqualTo("::1")

    // ... but they're included in toString().
    assertThat(parse("http://[::1]/").toString()).isEqualTo("http://[::1]/")

   *
   *  * A regular host name, like `android.com`.
   *
   *  * An IPv4 address, like `127.0.0.1`.
   *
   *  * An IPv6 address, like `::1`. Note that there are no square braces.
   *
   *  * An encoded IDN, like `xn--n3h.net`.
   *
   * | URL                   | `host()`        |
   * | :-------------------- | :-------------- |
   * | `http://android.com/` | `"android.com"` |

        String actualString = response.toString();
        assertTrue(actualString.startsWith("Trans2SetFileInformationResponse["),
                "The string representation should start with the class name.");
        assertTrue(actualString.endsWith("]"), "The string representation should end with a bracket.");
    }

<h2 id="restrictions">Implementation Restrictions for Programs Containing Data Races</h2>

<p>
The preceding section gave a formal definition of data-race-free program execution.
This section informally describes the semantics that implementations must provide
for programs that do contain races.
</p>

<p>
Any implementation can, upon detecting a data race,
report the race and halt execution of the program.

TypeName form of the LiteralType appears as an operand between the
<a href="#Keywords">keyword</a> and the opening brace of the block
of an "if", "for", or "switch" statement, and the composite literal
is not enclosed in parentheses, square brackets, or curly braces.
In this rare case, the opening brace of the literal is erroneously parsed
as the one introducing the block of statements. To resolve the ambiguity,

import okhttp3.internal.closeQuietly
import okio.Buffer
import okio.BufferedSource
import okio.ByteString
import okio.buffer
import okio.source

/** Replays prerecorded outgoing frames and records incoming frames.  */
class MockHttp2Peer : Closeable {
  private var frameCount = 0
  private var client = false
  private val bytesOut = Buffer()
  private var writer = Http2Writer(bytesOut, client)