Function enabled 

pub fn enabled() -> bool

Is the boundary re-delta on? true unless ZNIPPY_GIT_BOUNDARY_DELTA is set to 0, off or false.

It exists so the trade this module makes — wire bytes against clone CPU — can be measured as an A/B on one binary against one seeded store, rather than against two builds whose difference nobody can pin down afterwards. Read once and cached: this is on the path of every request, and a getenv per served object is exactly the kind of cost an engine that claims CPU should not add.

Off, every boundary entry is shipped whole, which is the behaviour before this module existed and is always correct.