error[E0277]: `Rc<Cell<i32>>` cannot be sent between threads safely
  --> tests/compile/non_send.rs:11:25
   |
11 |       lua.create_function(move |_, ()| {
   |           --------------- ^-----------
   |           |               |
   |  _________|_______________within this `[closure@$DIR/tests/compile/non_send.rs:11:25: 11:37]`
   | |         |
   | |         required by a bound introduced by this call
12 | |         Ok(data.get())
13 | |     })?
   | |_____^ `Rc<Cell<i32>>` cannot be sent between threads safely
   |
   = help: within `[closure@$DIR/tests/compile/non_send.rs:11:25: 11:37]`, the trait `Send` is not implemented for `Rc<Cell<i32>>`
note: required because it's used within this closure
  --> tests/compile/non_send.rs:11:25
   |
11 |     lua.create_function(move |_, ()| {
   |                         ^^^^^^^^^^^^
   = note: required for `[closure@$DIR/tests/compile/non_send.rs:11:25: 11:37]` to implement `mlua::types::MaybeSend`
note: required by a bound in `Lua::create_function`
  --> src/lua.rs
   |
   |         F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>,
   |                      ^^^^^^^^^ required by this bound in `Lua::create_function`