Fast output to stdout causes data loss about appscope

[iapaddler]

Changing the period for the reporting thread has a drastic effect.
At the default 10 sec period we see 238340 lines captured. Fairly consistent with the reported test.
At a period of 1 sec we see 965003 lines captured. Much closer.
3 tests at 1 sec period: 981673, 981660, 978691

Changed the definition of the period in config from secs to milliseconds.
At a 1ms period we see 1000000 lines
At a 5ms period we see 661325 lines

[iapaddler]

We no longer drop log/console data.
All event data queues are emptied much more frequently.
The drop test returns 1M console events in all cases tested.

2 updates:

1. All event queues are emptied every 1ms.
   This does not change the period at which summary/aggregation of metrics are emitted.
   The configured period is the definition for metric summaries.
   The configured period remains the delay for start of the periodic thread. This should change; need integ test for validation.
   This implies that it will be very rare to experience dropped events. Not guaranteed, very rare.

2. The ring buffer is no longer used as in in-memory queue for log/console data.
   All log/console events can, in theory, create app back pressure.
   All log/console events are delivered to the periodic thread by means of a UNIX domain socket.
   The UNIX socket is non-blocking on the read side and blocking on the send side.
   The blocking approach implies that no log data will be lost. It also enables back pressure in very rare cases.
   Kernel buffers would have to back up before any back pressure was experienced.