Pair Programming: Multi-Producer Single-Consumer Event Queue

Question

## Problem

In a CoderPad pair-programming session, implement a **multiple-producer single-consumer** event queue that merges events from different sources, handling edge cases. Complexity is discussed extensively.

## Example
```
producers push events; consumer drains in order; handle empty/burst
```

## Constraints
- Thread-safe; no lost events

## What Datadog looks for
Reported Datadog question. Collaborative coding, edge cases, and clear complexity reasoning.