val http2Connection =
      Http2Connection
        .Builder(client = true, taskRunner)
        .socket(socket, route.address.url.host)
        .listener(this)
        .pingIntervalMillis(pingIntervalMillis)
        .flowControlListener(flowControlListener)
        .build()
    this.http2Connection = http2Connection

              override fun writeTo(sink: BufferedSink) {
                sink.write(postBytes) // push bytes into the stream's buffer
                sink.flush() // Http2Connection.writeData subject to write window
                sink.close() // Http2Connection.writeData empty frame
              }
            },
        ),
      )
    val response = call.execute()
    assertThat(response.body.string()).isEqualTo("ABCDE")

import okhttp3.HttpUrl.Companion.toHttpUrl
import okhttp3.ResponseBody.Companion.toResponseBody
import okhttp3.internal.http.ExchangeCodec.Companion.DISCARD_STREAM_TIMEOUT_MILLIS
import okhttp3.internal.http2.Http2Connection.Companion.OKHTTP_CLIENT_WINDOW_SIZE
import okhttp3.testing.PlatformRule
import okio.BufferedSource
import okio.IOException
import okio.Path.Companion.toPath
import okio.fakefilesystem.FakeFileSystem
import okio.use