Add buffered channel to handle event bursts without blocking

[luiseterc]

1. Added buffered channels: Changed from unbuffered to buffered channels with a capacity of 1000 events, allowing the system to handle event bursts without blocking
2. Made SendEvent non-blocking: Replaced the blocking goroutine send with a non-blocking select statement that drops events when the buffer is full rather than accumulating goroutines

These changes should prevent the exporter from hanging during high-volume event bursts in AWS. The buffer accommodates temporary spikes, and if a sink truly can't keep up, events are dropped gracefully with warnings logged rather than causing goroutine buildup that freezes the system.

Fixes #6