val decoded = Punycode.decode(bufferA.readUtf8()) ?: return null

  // 4.1 Validate.

  // Must be NFC.
  if (decoded != normalizeNfc(decoded)) return null

  // TODO: Must not begin with a combining mark.
  // TODO: Each character must be 'valid' or 'deviation'. Not mapped.
  // TODO: CheckJoiners from IDNA 2008
  // TODO: CheckBidi from IDNA 2008, RFC 5893, Section 2.

  return Punycode.encode(decoded)

    // zero-width joiner
    assertThat(parse("http://h/\u200d").encodedPath).isEqualTo("/%E2%80%8D")
    // left-to-right mark
    assertThat(parse("http://h/\u200e").encodedPath).isEqualTo("/%E2%80%8E")
    // right-to-left mark
    assertThat(parse("http://h/\u200f").encodedPath).isEqualTo("/%E2%80%8F")
    // line separator
    assertThat(parse("http://h/\u2028").encodedPath).isEqualTo("/%E2%80%A8")

    server.enqueue(builder.build())
    val inputStream = getResponse(newRequest("/")).body.byteStream()
    assertThat(inputStream.markSupported(), "This implementation claims to support mark().")
      .isFalse()
    inputStream.mark(5)
    assertThat(readAscii(inputStream, 5)).isEqualTo("ABCDE")
    assertFailsWith<IOException> {
      inputStream.reset()
    }

import okhttp3.OkHttpClient
import okhttp3.Request

class PostForm {
  private val client = OkHttpClient()

  fun run() {
    val formBody =
      FormBody.Builder()
        .add("search", "Jurassic Park")
        .build()
    val request =
      Request(
        url = "https://en.wikipedia.org/w/index.php".toHttpUrl(),
        body = formBody,
      )

    client.newCall(request).execute().use { response ->

public final class PostForm {
  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    RequestBody formBody = new FormBody.Builder()
        .add("search", "Jurassic Park")
        .build();
    Request request = new Request.Builder()
        .url("https://en.wikipedia.org/w/index.php")
        .post(formBody)
        .build();

          ),
      ),
    )
  }

  @Test
  fun `certificate attributes`() {
    val certificate =
      HeldCertificate.Builder()
        .certificateAuthority(3)
        .commonName("Jurassic Park")
        .organizationalUnit("Gene Research")
        .addSubjectAlternativeName("*.example.com")
        .addSubjectAlternativeName("www.example.org")
        .validityInterval(-1000L, 2000L)
        .serialNumber(17L)

    assertThat(stringPrep("\u2ffb")).isNull()
  }

  @Test fun prohibitionChangeDisplayPropertiesOrDeprecated() {
    assertThat(stringPrep("\u0340")).isNull() // COMBINING GRAVE TONE MARK
    assertThat(stringPrep("\u200e")).isNull() // LEFT-TO-RIGHT MARK
    assertThat(stringPrep("\u206e")).isNull() // NATIONAL DIGIT SHAPES
    assertThat(stringPrep("\u206f")).isNull() // NOMINAL DIGIT SHAPES
  }

  @Throws(IOException::class)
  internal fun removeEntry(entry: Entry): Boolean {
    // If we can't delete files that are still open, mark this entry as a zombie so its files will
    // be deleted when those files are closed.
    if (!civilizedFileSystem) {
      if (entry.lockingSourceCount > 0) {
        // Mark this entry as 'DIRTY' so that if the process crashes this entry won't be used.
        journalWriter?.let {
          it.writeUtf8(DIRTY)

=== ":material-language-kotlin: Kotlin"
    ```kotlin
      private val client = OkHttpClient()

      fun run() {
        val formBody = FormBody.Builder()
            .add("search", "Jurassic Park")
            .build()
        val request = Request.Builder()
            .url("https://en.wikipedia.org/w/index.php")
            .post(formBody)
            .build()

309B          ; disallowed_STD3_mapped ; 0020 3099     # 1.1  KATAKANA-HIRAGANA VOICED SOUND MARK
309C          ; disallowed_STD3_mapped ; 0020 309A     # 1.1  KATAKANA-HIRAGANA SEMI-VOICED SOUND MARK
309D..309E    ; valid                                  # 1.1  HIRAGANA ITERATION MARK..HIRAGANA VOICED ITERATION MARK