/// <summary>
/// 异步的，通知应用程序，一个 <see cref="DbCommand"/> 已经执行。
/// </summary>
/// <param name="command">所执行的 <see cref="DbCommand"/> 对象。</param>
/// <param name="parameters"></param>
/// <param name="func">执行的方法。</param>
private async Task <T> AfterCommandExecutedAsync <T>(DbCommand command, ParameterCollection parameters, Func <Task <T> > func)
{
var result = default(T);
var period = await TimeWatcher.WatchAsync(async() => result = await func());
await HandleLogAsync(command, period);
command.SyncParameters(parameters);
command.ClearParameters();
return(result);
}