apply {
          parts += part
        }

      /** Assemble the specified parts into a request body. */
      fun build(): MultipartBody {
        check(parts.isNotEmpty()) { "Multipart body must have at least one part." }
        return MultipartBody(boundary, type, parts.toImmutableList())
      }
    }

  companion object {
    /**

import okhttp3.MediaType.Companion.toMediaType
import okhttp3.MultipartBody
import okhttp3.OkHttpClient
import okhttp3.Request
import okhttp3.RequestBody.Companion.asRequestBody

class PostMultipart {
  private val client = OkHttpClient()

  fun run() {
    // Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image
    val requestBody =
      MultipartBody
        .Builder()
        .setType(MultipartBody.FORM)

      |
      |--AaB03x--
      |
      """.trimMargin().replace("\n", "\r\n")
    val body =
      MultipartBody
        .Builder("AaB03x")
        .setType(MultipartBody.FORM)
        .addFormDataPart("submit-name", "Larry")
        .addFormDataPart(
          "files",
          null,
          MultipartBody
            .Builder("BbC04y")
            .addPart(

	public final fun addFormDataPart (Ljava/lang/String;Ljava/lang/String;Lokhttp3/RequestBody;)Lokhttp3/MultipartBody$Builder;
	public final fun addPart (Lokhttp3/Headers;Lokhttp3/RequestBody;)Lokhttp3/MultipartBody$Builder;
	public final fun addPart (Lokhttp3/MultipartBody$Part;)Lokhttp3/MultipartBody$Builder;

      )

    assertFailsWith<EOFException> {
      parts.nextPart()
    }
  }

  /** Confirm that [MultipartBody] and [MultipartReader] can work together. */
  @Test fun `multipart round trip`() {
    val body =
      MultipartBody
        .Builder("boundary")
        .setType(MultipartBody.PARALLEL)
        .addPart("Quick".toRequestBody("text/plain".toMediaType()))
        .addFormDataPart("color", "Brown")

    above. See [Jetty's overview][jetty_8_252] of the API change and its consequences.

 *  New: `MultipartReader` is a streaming decoder for [MIME multipart (RFC 2045)][rfc_2045]
    messages. It complements `MultipartBody` which is our streaming encoder.

    ```kotlin
    val response: Response = call.execute()
    val multipartReader = MultipartReader(response.body!!)

    multipartReader.use {
      while (true) {

      private val client = OkHttpClient()

      fun run() {
        // Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image
        val requestBody = MultipartBody.Builder()
            .setType(MultipartBody.FORM)
            .addFormDataPart("title", "Square Logo")
            .addFormDataPart("image", "logo-square.png",
                File("docs/images/logo-square.png").asRequestBody(MEDIA_TYPE_PNG))

 *  New: `OkHttpClient.webSocketCloseTimeout` configures how long a web socket connection will wait
    for a graceful shutdown before it performs an abrupt shutdown.

 *  Fix: Honor `RequestBody.isOneShot()` in `MultipartBody`

 *  Fix in `okhttp-coroutines`: Don't leak response bodies in `executeAsync()`. We had a bug where
    we didn't call `Response.close()` if the coroutine was canceled before its response was
    returned.