Task<UpdateResult> UpdateOneAsync(
	FilterDefinition<TDocument> filter,
	UpdateDefinition<TDocument> update,
	UpdateOptions options = null,
	CancellationToken cancellationToken = null
)

Function UpdateOneAsync ( 
	filter As FilterDefinition(Of TDocument),
	update As UpdateDefinition(Of TDocument),
	Optional options As UpdateOptions = Nothing,
	Optional cancellationToken As CancellationToken = Nothing
) As Task(Of UpdateResult)

abstract UpdateOneAsync : 
        filter : FilterDefinition<'TDocument> * 
        update : UpdateDefinition<'TDocument> * 
        ?options : UpdateOptions * 
        ?cancellationToken : CancellationToken 
(* Defaults:
        let _options = defaultArg options null
        let _cancellationToken = defaultArg cancellationToken null
*)
-> Task<UpdateResult>