Do not acknowledge flush() on start() for static tracks

            // But in this case we know the mixer thread (whether normal mixer or fast mixer)

            // isn't looking at this track yet:  we still hold the normal mixer thread lock,

            // and for fast tracks the track is not yet in the fast mixer thread's active set.

            // TODO: remove race condition on stop() followed by start().

            if (mSharedBuffer == 0) {  // only streaming tracks use flush().

                ServerProxy::Buffer buffer;

                buffer.mFrameCount = 1;

                (void) mAudioTrackServerProxy->obtainBuffer(&buffer, true /*ackFlush*/);

            }

        }

    } else {

        status = BAD_VALUE;

    }