Struct SolverCells 

pub struct SolverCells<'a> { /* private fields */ }

Crate-private cells the dispatch traits operate against. Passed to SolverDispatch::dispatch as a single bundle so each op implementation only depends on what it actually uses.

The struct itself is publicly visible because SolverDispatch is a public trait whose method takes a SolverCells<'_>, but every field is pub(crate) since the SendDn / SendSp newtypes leak FFI handles that have no stable external representation. External code wires custom solver ops by implementing SolverDispatch only when also living inside this crate.