Function tracing_read_deferral 

pub fn tracing_read_deferral<F, const BLOCK_SIZE: usize>(
    memory: &mut TracingMemory,
    ptr: u32,
    prev_timestamp: &mut u32,
) -> [F; BLOCK_SIZE]
where
    F: PrimeField32,

Reads register value at ptr from memory and records the previous timestamp. Reads are only done from address space [DEFERRAL_AS].