Add #sendNow(value) and #sendErrorNow(error)
Add #sendNow(value) and #sendErrorNow(error)

These functions allow to enqueue a value/error regardless of whether it can be consumed immediately and whether there is some spare capacity inside the chan's buffer.

Differences from #send(value) and #sendError(error):

- xxxNow() functions don't return Promise;
- xxxNow() functions perform the send immediately, on the same event loop tick;
- xxxNow() functions cannot be used with chan.select(...ops).

Differences from #sendSync(value) and #sendErrorSync(error):

- xxxNow() functions enqueue the send even if the value/error cannot be normally buffered/consumed; xxxSync() return false in this case;
- xxxNow() don't return anything.

Use these functions when you definitely need to perform a send, regardless of backpressure, and don't care when it is consumed or buffered within the chan's defined buffer capacity.

skozin/cochan