Macro trace_state_change 

macro_rules! trace_state_change {
    ($component:expr, $from:expr, $to:expr) => { ... };
    ($component:expr, $from:expr, $to:expr, $($field:tt)*) => { ... };
}

Log a state change with before/after values.

Example

use mabi_core::trace_state_change;

trace_state_change!("engine", "stopped", "running");