https://learn.microsoft.com/en-us/dotnet/api/microsoft.exchange.webservices.data.exchangeservice.getuseravailability?view=exchange-ews-api&redirectedfrom=MSDN
ExchangeService.GetUserAvailability Method (Microsoft.Exchange.WebServices.Data) | Microsoft Learn
Retrieves detailed information about the availability of a set of users, rooms, and resources during a specified time period.
microsoft exchangemethodwebservicesdatalearn