Several methods have a similar descriptor to the following in the docs:
k and v contents may be modified after returning from Set.
Upon first reading, I assumed that the Set() method would modify the k and v byte arrays and copies should be passed into the fastcache methods.
I couldn't believe it and only after spending some time digging in the source did I realize that these sentences probably meant that the fastcache methods themselves stored copies of the k and v arrays and that you didn't have to worry about reusing the originals.
Just a heads up, I found the particular wording confusing, perhaps consider a slightly different wording.