@Test
  fun multipartBodyBuilder() {
    val requestBody = "".toRequestBody(null)
    var builder: MultipartBody.Builder = MultipartBody.Builder()
    builder = MultipartBody.Builder("")
    builder = builder.setType("".toMediaType())
    builder = builder.addPart(requestBody)
    builder = builder.addPart(headersOf(), requestBody)
    builder = builder.addPart(null, requestBody)
    builder = builder.addFormDataPart("", "")