Function boolean_dispatch 

pub fn boolean_dispatch(
    mesh_a: &ManifoldImpl,
    mesh_b: &ManifoldImpl,
    op: OpType,
    engine: BooleanEngine,
    token: Option<&CancelToken>,
) -> ManifoldImpl

Route a boolean to the requested engine (types::BooleanEngine).

Auto resolves per pair: Robust iff either operand carries soup geometry, else Exact. Exact with a soup operand yields an empty result with Error::NotManifold (the guard inside boolean_with_token); no panic-catching is involved anywhere — dispatch is input-based only.