* For everyone who gave me suggestions for my unexpectedly slow execution times issue, I wanted to follow up with the solution.

I turns out it was XIP--the Pico 2's flash is not able to keep up with the μC; running instructions directly from it introduces wait states--perhaps obvious in hindsight--but thank you James Munns for the XIP suggestion!  I'm not sure how long it would have taken me to suspect flash itself, but I _know_ it would have been a while!!  😅

In addition to being marked with the `#[inline(always)]` hint, my `cycle_count()` routine is now marked to be placed in SRAM by the linker.  I ran into a minor issue when I only marked the function itself to be placed in SRAM: when it is being called from a function in flash, `#[inline(always)]` hint will win and the function will run from flash--continuing to be slow.  So once I ensured the caller was also running from SRAM, time between consecutive `cycle_count()` calls fell from 237 to 33 clock cycles in debug and 115 to 8 clock cycles in release mode--the latter representing a 14x performance increase! 😎

Excerpt from `defmt` spew (release mode):
\`Instant::now().as\_ticks(): 75008231 INFO  Consecutive read 1 & 2: 75006709,75006717 = **Δ8cc**
└─ \<mod path> @ └─ \<invalid location: defmt frame-index: 7>:0

This is a great community--thanks to everyone for your help in figuring this out!