Samsung appliances silently drop CoAP requests when hit faster than their
firmware ceiling (~8–14 req/s measured; dishwasher unknown). Multi-block
Block2 fetches on LAN hit ~100 req/s instantaneously, causing the observed
burst timeouts on block 4 and block 10 of /device/0.
Adds rate_limit_rps (default 5 req/s / 200 ms) to DtlsCoapSession with a
pace() method that enforces the inter-block delay via _stop.wait() so session
teardown interrupts the sleep cleanly. Coordinator calls pace() between hrefs
in _poll_hrefs_blocking. Also adds device IP to all GET log lines for easier
per-device filtering.
Marc Billow
022a192bca