BeforeDatasetUpdateHook (Charba - J2CL and GWT charts library based on CHART.JS)

```
public interface BeforeDatasetUpdateHook
```
Called before updating the 'chart' dataset at the given 'args.index'.
If any plugin returns false, the datasets update is cancelled until another 'update' is triggered.

Author:

Andrea "Stock" Stocchero

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`onBeforeDatasetUpdate(IsChart chart, PluginDatasetArgument item)`	Called before updating the 'chart' dataset at the given 'args.index'. If any plugin returns `false`, the datasets update is cancelled until another 'update' is triggered.

- Method Detail
  - onBeforeDatasetUpdate
```
boolean onBeforeDatasetUpdate(IsChart chart,
                              PluginDatasetArgument item)
```
    Called before updating the 'chart' dataset at the given 'args.index'.
    If any plugin returns false, the datasets update is cancelled until another 'update' is triggered.
    
    Parameters:
    
    chart - the chart instance.
    
    item - the dataset item.
    
    Returns:
    
    false to cancel the chart datasets drawing.