MultipartBody.Builder("123")
        .addPart("Hello, World!".toOneShotRequestBody())
        .build()

    assertThat(body.isOneShot()).isEqualTo(true)

    val buffer = Buffer()
    body.writeTo(buffer)
    assertThat(body.contentLength()).isEqualTo(buffer.size)
    assertThat(buffer.readUtf8()).isEqualTo(expected)
  }

  fun String.toOneShotRequestBody(): RequestBody {
    return object : RequestBody() {