<https://msdn.microsoft.com/en-us/library/office/dn659837%28v=exchg.150%29.aspx>

According to link above, we can caching the information for Autodiscover. 

The question is:

1) Should i serialize ExchangeService object to xml or just cache some of the properties (which properties) ? (I want to improve performance of the system because autodiscoverurl is too slow)