Aggregates input events. For example, suppose the following inputs are received between frames:
left mouse button down, mouse move, mouse move, left mouse button up. These events will be aggregated into
one event with a start and end position of the mouse.
    
| Name | Type | Default | Description | 
|---|---|---|---|
| canvas | HTMLCanvasElement | document | optional The element to handle events for. | 
Members
    Gets whether any mouse button is down, a touch has started, or the wheel has been moved.
currentMousePosition : Cartesian2
    Gets the current mouse position.
Methods
    Removes mouse listeners held by this object.
Once an object is destroyed, it should not be used; calling any function other than
Once an object is destroyed, it should not be used; calling any function other than
isDestroyed will result in a DeveloperError exception.  Therefore,
assign the return value (undefined) to the object as done in the example.
Throws:
- 
    DeveloperError : This object was destroyed, i.e., destroy() was called.
Example:
handler = handler && handler.destroy();See:
    Gets the time the button was pressed or the touch was started.
    
| Name | Type | Description | 
|---|---|---|
| type | CameraEventType | The camera event type. | 
| modifier | KeyboardEventModifier | optional The keyboard modifier. | 
Returns:
    The time the button was pressed or the touch was started.
    
    Gets the time the button was released or the touch was ended.
    
| Name | Type | Description | 
|---|---|---|
| type | CameraEventType | The camera event type. | 
| modifier | KeyboardEventModifier | optional The keyboard modifier. | 
Returns:
    The time the button was released or the touch was ended.
    
    Gets the start and end position of the last move event (not the aggregated event).
    
| Name | Type | Description | 
|---|---|---|
| type | CameraEventType | The camera event type. | 
| modifier | KeyboardEventModifier | optional The keyboard modifier. | 
Returns:
    Gets the aggregated start and end position of the current event.
    
| Name | Type | Description | 
|---|---|---|
| type | CameraEventType | The camera event type. | 
| modifier | KeyboardEventModifier | optional The keyboard modifier. | 
Returns:
getStartMousePosition(type, modifier) → Cartesian2
    Gets the mouse position that started the aggregation.
    
| Name | Type | Description | 
|---|---|---|
| type | CameraEventType | The camera event type. | 
| modifier | KeyboardEventModifier | optional The keyboard modifier. | 
Returns:
    The mouse position.
    
    Gets whether the mouse button is down or a touch has started.
    
| Name | Type | Description | 
|---|---|---|
| type | CameraEventType | The camera event type. | 
| modifier | KeyboardEventModifier | optional The keyboard modifier. | 
Returns:
    Whether the mouse button is down or a touch has started.
    
    Returns true if this object was destroyed; otherwise, false.
If this object was destroyed, it should not be used; calling any function other than
If this object was destroyed, it should not be used; calling any function other than
isDestroyed will result in a DeveloperError exception.
Returns:
true if this object was destroyed; otherwise, false.
    Gets if a mouse button down or touch has started and has been moved.
    
| Name | Type | Description | 
|---|---|---|
| type | CameraEventType | The camera event type. | 
| modifier | KeyboardEventModifier | optional The keyboard modifier. | 
Returns:
    Returns 
    
true if a mouse button down or touch has started and has been moved; otherwise, false
    Signals that all of the events have been handled and the aggregator should be reset to handle new events.
