<ExtensionAttribute()>
Public Overloads Shared Function SingleOrDefault( _
   ByVal source As IEntityScalarQuery, _
   ByVal predicateDescription As IPredicateDescription, _
   Optional ByVal userCallback As Action(Of EntityScalarQueryOperation), _
   Optional ByVal userState As Object _
) As EntityScalarQueryOperation

Dim source As IEntityScalarQuery
Dim predicateDescription As IPredicateDescription
Dim userCallback As Action(Of EntityScalarQueryOperation)
Dim userState As Object
Dim value As EntityScalarQueryOperation
 
value = EntityScalarAsyncExtensions.SingleOrDefault(source, predicateDescription, userCallback, userState)

[ExtensionAttribute()]
public static EntityScalarQueryOperation SingleOrDefault( 
   IEntityScalarQuery source,
   IPredicateDescription predicateDescription,
   Action<EntityScalarQueryOperation> userCallback,
   object userState
)

[ExtensionAttribute()]
public:
static EntityScalarQueryOperation^ SingleOrDefault( 
   IEntityScalarQuery^ source,
   IPredicateDescription^ predicateDescription,
   Action<EntityScalarQueryOperation^>^ userCallback,
   Object^ userState
) 

public void AsyncSingleOrDefaultWithPredicate() {
   var op = _entityManager.Employees.AsScalarAsync().SingleOrDefault(e => e.Id == 1);
   op.Completed += (o, e) => {
     var emp = e.Result;
   };
 }