Update pep-0810.rst

Author: pablogsal

peps/pep-0810.rst

@@ -586,7 +586,10 @@ This PEP adds the following new functions to manage the lazy imports filter:
 The filter function is called for every potentially lazy import, and must
 return ``True`` if the import should be lazy. This allows for fine-grained
 control over which imports should be lazy, useful for excluding modules with
-known side-effect dependencies or registration patterns.
+known side-effect dependencies or registration patterns. The filter function
+is called at the point of execution of the lazy import or lazy from import
+statement, not at the point of reification. The filter function may be
+called concurrently.
 
 The filter mechanism serves as a foundation that tools, debuggers, linters,
 and other ecosystem utilities can leverage to provide better lazy import