Have 'metasploit/framework/spec/threads/suite/logger' generate a UUID
for each Thread. This UUID is printed on the "BEGIN Thread.new caller"
line and is assigned as a thread-local variable,
'metasploit/framework/spec/threads/logger/uuid'. In `after(:suite)`,
the log can be parsed to map the caller back to each UUID and then only
the UUID of the still existing threads is used to look up the caller and
print their stacktraces. This means only leaked threads callers will be
printed.
Luke Imhoff