Function trampoline

pub(crate) unsafe fn trampoline<F, R>(body: F) -> R
where
    F: for<'py> FnOnce(Python<'py>) -> PyResult<R> + UnwindSafe,
    R: PyCallbackOutput,

Implementation of trampoline functions, which sets up a GILPool and calls F.

Panics during execution are trapped so that they don’t propagate through any outer FFI boundary.

The GIL must already be held when this is called.