A 
    
DataSource implementation which can be used to manually manage a group of entities.
| Name | Type | Description | 
|---|---|---|
| name | String | optional A human-readable name for this instance. | 
Example:
var dataSource = new Cesium.CustomDataSource('myData');
var entity = dataSource.entities.add({
   position : Cesium.Cartesian3.fromDegrees(1, 2, 0),
   billboard : {
       image : 'image.png'
   }
});
viewer.dataSources.add(dataSource);Members
changedEvent : Event
    Gets an event that will be raised when the underlying data changes.
    Gets or sets the clock for this instance.
clustering : EntityCluster
    Gets or sets the clustering options for this data source. This object can be shared between multiple data sources.
    Gets the collection of 
Entity instances.
errorEvent : Event
    Gets an event that will be raised if an error is encountered during processing.
    Gets or sets whether the data source is currently loading data.
loadingEvent : Event
    Gets an event that will be raised when the data source either starts or stops loading.
    Gets or sets a human-readable name for this instance.
    Gets whether or not this data source should be displayed.
