Metadata (numaflow-java 0.0.1 API)

```
public interface Metadata
```
Metadata contains methods to get the metadata for the reduce operation.

- Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method Description
  
  IntervalWindow getIntervalWindow()
  method to get the interval window.

- Method Detail
  - getIntervalWindow
```
IntervalWindow getIntervalWindow()
```
    method to get the interval window.
    
    Returns:
    
    IntervalWindow which has the window information