Bridge data corruption

[kevinmehall]

Seems to happen with lots of small packets, and is commonly triggered with io.js versions that don't support cork on domain sockets (1.4 did support it, 2.0.2 does not).

Probably the SYNC handler takes too long and the firmware is not ready for the SPI transfer.

We need a tool to spam the ports with random echo commands, and a tool to watch the logic analyzer trace on a firmware patched to toggle a GPIO in the IRQ and watch for timing violations.

[rwaldron]

@kevinmehall where does this stand? Is there a bug filed with io.js?

[kevinmehall]

The original problem that made me suspect data corruption on split packets was actually a tessel.js issue and solved by #48. There are no known data corruption bugs in the bridge, but definitely could use more testing, so I am closing this issue in favor of #70.

cork is a performance optimization, but shouldn't be required for correctness. There was an io.js pull request, which I closed after they merged something equivalent. Then it got reverted because it broke something on Windows. I haven't followed progress on it recently.