Provides functionality for ImageryProviders that have time dynamic imagery
    
| Name | Type | Description | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| options | Object | Object with the following properties: 
 | 
Members
    Gets or sets a clock that is used to get keep the time used for time dynamic parameters.
currentInterval : TimeInterval
    Gets the current interval.
    Gets or sets a time interval collection.
Methods
    Checks if the next interval is approaching and will start preload the tile if necessary. Otherwise it will
just add the tile to a list to preload when we approach the next interval.
    
| Name | Type | Description | 
|---|---|---|
| x | Number | The tile X coordinate. | 
| y | Number | The tile Y coordinate. | 
| level | Number | The tile level. | 
| request | Request | optional The request object. Intended for internal use only. | 
    Gets the tile from the cache if its available.
    
| Name | Type | Description | 
|---|---|---|
| x | Number | The tile X coordinate. | 
| y | Number | The tile Y coordinate. | 
| level | Number | The tile level. | 
| request | Request | optional The request object. Intended for internal use only. | 
Returns:
    A promise for the image that will resolve when the image is available, or
         undefined if the tile is not in the cache.
    
