Picos_tlsSourceThread-local storage.
Note that here "thread" refers to system level threads rather than fibers or domains. In case a system level thread implementation, i.e. the threads.posix library, is not available, this will use Picos_domain.DLS.
Represents a key for storing values of type 'a in storage associated with threads.
get key returns the value associated with the key in the storage associated with the current thread.