Constant total_space::MAX_COUNT

pub const MAX_COUNT: usize = 6;

The maximal number of alternative actions in a reaction, payloads in an activity or emitted messages within an action.

Making this static allows us to avoid dynamic memory allocation when computing reactions which speeds things up a lot. As a result, the size of a reaction is pretty large, but we allocate it on the stack so that seems like an acceptable trade-off.