Mutex requires data to by Sync

[peopleskai]

Hi,

In line https://github.com/lobaro/FreeRTOS-rust/blob/master/freertos-rust/src/mutex.rs#L11 we can see the Mutex API requires the data it holds to have Sync trait for it to implement Sync.

I wanted to understand the reason for this. I believe in the standard library Mutex will be Send+Sync if the data type is Send. https://doc.rust-lang.org/std/sync/struct.Mutex.html#impl-Sync-for-Mutex%3CT%3E

This makes sense since Mutex is what provides the Sync feature for the data. If the data is already Sync, why would it need to be wrapped in a Mutex?