MediaType mediaType = addKnownType(new MediaType(type, subtype, UTF_8_CONSTANT_PARAMETERS));
    mediaType.parsedCharset = Optional.of(UTF_8);
    return mediaType;
  }

  @CanIgnoreReturnValue
  private static MediaType addKnownType(MediaType mediaType) {
    knownTypes.put(mediaType, mediaType);
    return mediaType;
  }

  /*
   * The following constants are grouped by their type and ordered alphabetically by the constant

    MediaType mediaType = addKnownType(new MediaType(type, subtype, UTF_8_CONSTANT_PARAMETERS));
    mediaType.parsedCharset = Optional.of(UTF_8);
    return mediaType;
  }

  @CanIgnoreReturnValue
  private static MediaType addKnownType(MediaType mediaType) {
    knownTypes.put(mediaType, mediaType);
    return mediaType;
  }

  /*
   * The following constants are grouped by their type and ordered alphabetically by the constant

	public static final fun create (Lokhttp3/MediaType;Lokio/ByteString;)Lokhttp3/RequestBody;
	public static final fun create (Lokhttp3/MediaType;[B)Lokhttp3/RequestBody;
	public static final fun create (Lokhttp3/MediaType;[BI)Lokhttp3/RequestBody;
	public static final fun create (Lokhttp3/MediaType;[BII)Lokhttp3/RequestBody;

        try {
            if (useFilename) {
                final MediaType mediaType = mimeTypes.detect(null, metadata);
                if (!MediaType.OCTET_STREAM.equals(mediaType)) {
                    return mediaType.getType() + "/" + mediaType.getSubtype();
                }
            }

            final MediaType mediaType = mimeTypes.detect(is == null || is.markSupported() ? is : new BufferedInputStream(is), metadata);

    @JvmName("create")
    fun String.toRequestBody(contentType: MediaType? = null): RequestBody {
      val (charset, finalContentType) = contentType.chooseCharset()
      val bytes = toByteArray(charset)
      return bytes.toRequestBody(finalContentType, 0, bytes.size)
    }

    @JvmStatic
    @JvmName("create")
    fun ByteString.toRequestBody(contentType: MediaType? = null): RequestBody =
      object : RequestBody() {

	public static final fun create (Lokhttp3/MediaType;Lokio/ByteString;)Lokhttp3/RequestBody;
	public static final fun create (Lokhttp3/MediaType;[B)Lokhttp3/RequestBody;
	public static final fun create (Lokhttp3/MediaType;[BI)Lokhttp3/RequestBody;
	public static final fun create (Lokhttp3/MediaType;[BII)Lokhttp3/RequestBody;

  }

  @Test
  fun mediaType() {
    val mediaType: MediaType = "".toMediaType()
    val defaultCharset: Charset? = mediaType.charset()
    val charset: Charset? = mediaType.charset(Charsets.UTF_8)
    val type: String = mediaType.type
    val subtype: String = mediaType.subtype
    val parse: MediaType? = "".toMediaTypeOrNull()
  }

  @Test
  fun mockResponse() {

import java.io.File;
import java.io.IOException;

public final class UploadProgress {
  private static final String IMGUR_CLIENT_ID = "9199fdef135c122";
  private static final MediaType MEDIA_TYPE_PNG = MediaType.get("image/png");

  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    // Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image

        "}}",
    )
  }

  @Test
  fun gzip() {
    val mediaType = "text/plain; charset=utf-8".toMediaType()
    val originalBody = "This is the original message".toRequestBody(mediaType)
    assertThat(originalBody.contentLength()).isEqualTo(28L)
    assertThat(originalBody.contentType()).isEqualTo(mediaType)

    val request =
      Request
        .Builder()
        .url("https://square.com/")

=== ":material-language-java: Java"
    ```java
      public static final MediaType MEDIA_TYPE_MARKDOWN
          = MediaType.parse("text/x-markdown; charset=utf-8");

      private final OkHttpClient client = new OkHttpClient();

      public void run() throws Exception {
        RequestBody requestBody = new RequestBody() {
          @Override public MediaType contentType() {
            return MEDIA_TYPE_MARKDOWN;
          }