Concurrent tool executor implementation.

## ConcurrentToolExecutor

```python
class ConcurrentToolExecutor(ToolExecutor)
```

Defined in: [src/strands/tools/executors/concurrent.py:20](https://github.com/strands-agents/harness-sdk/blob/main/strands-py/src/strands/tools/executors/concurrent.py#L20)

Concurrent tool executor.