"Types lasting for the lifetime of the program" is accounted for by 'static lifetime. I am referring to the use of _static_ and _static mut_ declarations in th

"Types lasting for the lifetime of the program" is accounted for by 'static lifetime. I am referring to the use of _static_ and _static mut_ declarations in the code, which is not quite the same thing. The interesting question is whether it might be possible to have multiple "collection" threads within a single instance of the program, each working on independent graphs.