Add an optional ring buffer which holds the encoded trace data. When
included the buffer registers automatically and captures and stores
encoded trace events. This is a work in progress, future CLs will add
more/better methods of accessing the data.
Test: passes the included tests.
Change-Id: I0744547471086171dd47a22ed53312b1033930c7
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/13322
Commit-Queue: Rob Oliver <rgoliver@google.com>
Reviewed-by: (☞ﾟ∀ﾟ)☞ Tennessee Carmel-Veilleux <tennessee@google.com>
