[statsd] add a statsd_timethis context manager
This context manager allows to report to statsd the execution time of any
piece of code, without the need for it to be a function or a method, like::
def some_function():
do_stuff()
with statsd_timethis('some context message'):
do_that()
ensure_this()
.. _rset_module:
:mod:`cubicweb.rset`
====================
.. automodule:: cubicweb.rset
.. autoclass:: ResultSet
:members: