val contentType = "text/plain".toMediaType()
    val body = "\u0800".toRequestBody(contentType)
    assertThat(body.contentType()).isEqualTo("text/plain; charset=utf-8".toMediaType())
    assertThat(body.contentLength()).isEqualTo(3)
    assertThat(bodyToHex(body)).isEqualTo("e0a080")
  }

  @Test
  fun stringWithNonDefaultCharsetSpecified() {
    val contentType = "text/plain; charset=utf-16be".toMediaType()

      |Content-Disposition: form-data; name="files"
      |Content-Type: multipart/mixed; boundary=BbC04y
      |
      |--BbC04y
      |Content-Disposition: file; filename="file1.txt"
      |Content-Type: text/plain; charset=utf-8
      |
      |... contents of file1.txt ...
      |--BbC04y
      |Content-Disposition: file; filename="file2.gif"
      |Content-Transfer-Encoding: binary
      |Content-Type: image/gif
      |

topic            (string)    Kafka topic used for bucket notifications
sasl_username    (string)    username for SASL/PLAIN or SASL/SCRAM authentication
sasl_password    (string)    password for SASL/PLAIN or SASL/SCRAM authentication
sasl_mechanism   (string)    sasl authentication mechanism, default 'plain'
tls_client_auth  (string)    clientAuth determines the Kafka server's policy for TLS client auth

    val interceptorResponse =
      Response.Builder()
        .request(request)
        .protocol(Protocol.HTTP_1_1)
        .code(200)
        .message("Intercepted!")
        .body("abc".toResponseBody("text/plain; charset=utf-8".toMediaType()))
        .build()
    client =
      client.newBuilder()
        .addInterceptor(Interceptor { chain: Interceptor.Chain? -> interceptorResponse })
        .build()

  }

  private fun sleepingRequestBody(sleepMillis: Int): RequestBody {
    return object : RequestBody() {
      override fun contentType(): MediaType? {
        return "text/plain".toMediaTypeOrNull()
      }

      @Throws(IOException::class)
      override fun writeTo(sink: BufferedSink) {
        try {
          sink.writeUtf8("abc")
          sink.flush()

is-plain-obj@^2.1.0:
  version "2.1.0"
  resolved "https://registry.yarnpkg.com/is-plain-obj/-/is-plain-obj-2.1.0.tgz#45e42e37fccf1f40da8e5f76ee21515840c09287"
  integrity sha512-YWnfyRwxL/+SsrWYfOpUtz5b3YD+nyfkHvjbcanzk8zgyO4ASD67uVMRt8k5bM4lLMDnXfriRhOpemw+NfT1eA==

is-plain-object@^2.0.4:
  version "2.0.4"

    val call =
      client.newCall(
        Request(
          url = server.url("/foo"),
          body =
            object : RequestBody() {
              override fun contentType(): MediaType = "text/plain; charset=utf-8".toMediaType()

              override fun writeTo(sink: BufferedSink) {
                sink.write(postBytes)
              }
            },
        ),
      )

```

### `HTMLResponse`

Takes some text or bytes and returns an HTML response, as you read above.

### `PlainTextResponse`

Takes some text or bytes and returns an plain text response.

```Python hl_lines="2  7  9"
{!../../../docs_src/custom_response/tutorial005.py!}
```

### `JSONResponse`

Takes some data and returns an `application/json` encoded response.

class CommonRequestBodyTest {
  @Test
  fun correctContentType() {
    val body = "Body"
    val requestBody = body.toRequestBody(MediaType("text/plain", "text", "plain", arrayOf()))

    val contentType = requestBody.contentType()!!

    assertThat(contentType.mediaType).isEqualTo("text/plain; charset=utf-8")
    assertThat(contentType.parameter("charset")).isEqualTo("utf-8")
  }

instead of being called directly (as it would block the server).

If you are coming from another async framework that does not work in the way described above and you are used to defining trivial compute-only *path operation functions* with plain `def` for a tiny performance gain (about 100 nanoseconds), please note that in **FastAPI** the effect would be quite opposite. In these cases, it's better to use `async def` unless your *path operation functions* use code that performs blocking <abbr...