MultipartBody.Builder()
        .addPart(headersOf("Foo", "Bar"), "Baz".toRequestBody(null))
        .build()
    assertThat(body.parts.size).isEqualTo(1)
    val part1Buffer = Buffer()
    val part1 = body.part(0)
    part1.body.writeTo(part1Buffer)
    assertThat(part1.headers).isEqualTo(headersOf("Foo", "Bar"))
    assertThat(part1Buffer.readUtf8()).isEqualTo("Baz")
  }

  @Test
  fun nonAsciiFilename() {