<ExtensionAttribute()>
Public Overloads Shared Function Count(Of TSource)( _
   ByVal source As IEntityScalarQuery(Of TSource), _
   Optional ByVal userCallback As Action(Of EntityScalarQueryOperation(Of Integer)), _
   Optional ByVal userState As Object _
) As EntityScalarQueryOperation(Of Integer)

Dim source As IEntityScalarQuery(Of TSource)
Dim userCallback As Action(Of EntityScalarQueryOperation(Of Integer))
Dim userState As Object
Dim value As EntityScalarQueryOperation(Of Integer)
 
value = EntityScalarAsyncExtensions.Count(Of TSource)(source, userCallback, userState)

[ExtensionAttribute()]
public static EntityScalarQueryOperation<int> Count<TSource>( 
   IEntityScalarQuery<TSource> source,
   Action<EntityScalarQueryOperation<int>> userCallback,
   object userState
)

[ExtensionAttribute()]
public:
static EntityScalarQueryOperation<int>^ Countgeneric<typename TSource>
( 
   IEntityScalarQuery<TSource^>^ source,
   Action<EntityScalarQueryOperation<int>^>^ userCallback,
   Object^ userState
) 

public void AsyncCount() {
  var op = _entityManager.Employees.AsScalarAsync().Count();
  op.Completed += (o, e) => {
    var ct = e.Result;
  };
}