I like to think of it as detachment. We know about practicing detachment when it concerns "things". I try to carry that over into other areas of my life, such as people and outcomes.
For example, I had a job in Charlotte, NC on the 8th and 9th of January that was going to be pretty lucrative for me. I got an email a couple days before Christmas that it canceled. 10 months ago I would have been hugely disappointed by this. However, I didn't even give it a second thought. I'm just going with the flow
Before I would have spent time and energy dwelling on the loss, the disappointment, the big check that WOULD NOT be coming in the mail, etcetera. Since I don't do that anymore, there are few days on my calendar that remain unfilled!