注意：该访问调用时如果收到非字符串数据则会抛出异常。同时，该方法不可在IWebSocket的接收数据事件（插件）中使用。 相关用法请按照ReadAsync(CancellationToken)进行。
public static Task ReadStringAsync(
this IWebSocket webSocket,
ByteBlock byteBlock,
CancellationToken token = default
)<ExtensionAttribute>
Public Shared Function ReadStringAsync (
webSocket As IWebSocket,
byteBlock As ByteBlock,
Optional token As CancellationToken = Nothing
) As Task[<ExtensionAttribute>]
static member ReadStringAsync :
webSocket : IWebSocket *
byteBlock : ByteBlock *
?token : CancellationToken
(* Defaults:
let _token = defaultArg token new CancellationToken()
*)
-> Task