Cell

Reference Video | Rust doc - cell (module), Cell (struct)

• Allows mutable sharing
• No one has a reference to the thing inside a cell. so anyone can modify the cell itself
• Does not implement Sync
• can get the value only if:
  1. you have a mutable reference to it (at which point you dont really need a cell)
  2. the type inside implements Copy
• therefore a cell is usually used for small Copy types
• useful for when you want multiple things referencing the same thing in a single threaded system
• Technically all the magic of a Cell is done int the UnsafeCell implementation The compiler has extra info about UnsafeCell and considers it differently. This allows for such behaviour.
• UnsafeCell implements !Sync and a bunch of other features
• UnsafeCell also allows us to get an exclusive, mutable reference from a shared reference. This is allowed because the compiler trusts the guy :)