requestBody.flush()
      assertThat(responseBody.readUtf8Line())
        .isEqualTo("response F")
      requestBody.close()
      assertThat(responseBody.readUtf8Line()).isNull()
    }
    body.awaitSuccess()
  }

  @Test
  fun trueDuplexServerWritesFirst() {
    enableProtocol(Protocol.HTTP_2)
    val body =
      MockSocketHandler()
        .sendResponse("response A\n")

            action(socket)
          }
        }
      }
      return@FutureTask null
    }
  }

  /** Returns once all stream actions complete successfully. */
  fun awaitSuccess() {
    val futureTask =
      results.poll(5, TimeUnit.SECONDS)
        ?: throw AssertionError("no onRequest call received")
    futureTask.get(5, TimeUnit.SECONDS)
  }

            sink.flush()

            assertThat(source.readUtf8Line()).isEqualTo("server says goodbye")

            assertThat(source.exhausted()).isTrue()
          }
        }
        socketHandler.awaitSuccess()
      }
  }

  @Test
  fun upgrade() {
    executeAndCheckUpgrade(upgradeRequest())
  }

  @Test
  fun upgradeWithEmptyRequestBody() {