Investigate/replace eventtracking usage of thread local

[ormsbee]

This is not async-friendly:

event-tracking/eventtracking/locator.py

Lines 29 to 54 in a6f1079

	class ThreadLocalContextLocator:
	"""
	Returns a different context depending on the thread that the locator
	was called from. Thus, contexts can be isolated from one another
	on thread boundaries.
	Note that this makes use of `threading.local(),` which is typically
	monkey-patched by alternative python concurrency frameworks (like `gevent`).
	Calls to `threading.local()` are delayed until first usage in order to
	give the third-party concurrency libraries an opportunity to monkey monkey
	patch it.
	"""
	def __init__(self):
	self.thread_local_data = None
	def get(self):
	"""Return a reference to a thread-specific context"""
	if not self.thread_local_data:
	self.thread_local_data = threading.local()
	if not hasattr(self.thread_local_data, 'context'):
	self.thread_local_data.context = OrderedDict()
	return self.thread_local_data.context