public abstract Task<IAsyncCursor<TField>> DistinctAsync<TField>(
	FieldDefinition<TDocument, TField> field,
	FilterDefinition<TDocument> filter,
	DistinctOptions options = null,
	CancellationToken cancellationToken = null
)

Public MustOverride Function DistinctAsync(Of TField) ( 
	field As FieldDefinition(Of TDocument, TField),
	filter As FilterDefinition(Of TDocument),
	Optional options As DistinctOptions = Nothing,
	Optional cancellationToken As CancellationToken = Nothing
) As Task(Of IAsyncCursor(Of TField))

abstract DistinctAsync : 
        field : FieldDefinition<'TDocument, 'TField> * 
        filter : FilterDefinition<'TDocument> * 
        ?options : DistinctOptions * 
        ?cancellationToken : CancellationToken 
(* Defaults:
        let _options = defaultArg options null
        let _cancellationToken = defaultArg cancellationToken null
*)
-> Task<IAsyncCursor<'TField>>