From that section: "most Google developers use a common control flow library to construct callbacks" OpenTelemetry can't guarantee that their users will use a

From that section: "most Google developers use a common control flow library to construct callbacks" OpenTelemetry can't guarantee that their users will use a specific library to create callbacks and can't then ensure that this library wraps callbacks with the appropriate threadlocal setup. Users would by default run into problems unless they take a number of precautionary steps.