Tests that interception works with multiple clients.
-- request stage for client 1 and client 2
client 2: intercepted request to http://127.0.0.1:8000/devtools/network/resources/resource.php
client 1: intercepted request to http://127.0.0.1:8000/devtools/network/resources/resource.php
-- request stage for client 1, both stages for client 2
client 2: intercepted request to http://127.0.0.1:8000/devtools/network/resources/resource.php
client 1: intercepted request to http://127.0.0.1:8000/devtools/network/resources/resource.php
client 2: intercepted response 200 from http://127.0.0.1:8000/devtools/network/resources/resource.php
-- both stages for client 1 and client 2
client 2: intercepted request to http://127.0.0.1:8000/devtools/network/resources/resource.php
client 1: intercepted request to http://127.0.0.1:8000/devtools/network/resources/resource.php
client 1: intercepted response 200 from http://127.0.0.1:8000/devtools/network/resources/resource.php
client 2: intercepted response 200 from http://127.0.0.1:8000/devtools/network/resources/resource.php
-- mock response from client 1
client 2: intercepted request to http://127.0.0.1:8000/devtools/network/resources/resource.php
client 1: rejecting request to http://127.0.0.1:8000/devtools/network/resources/resource.php
client 2: intercepted response 418 from http://127.0.0.1:8000/devtools/network/resources/resource.php
-- mock response from client 3
client 3: resolving response to http://127.0.0.1:8000/devtools/network/resources/resource.php
response: Hello, world!
-- url rewrite from client 3
client 3: overriding URL from http://127.0.0.1:8000/devtools/network/resources/resource.php to http://127.0.0.1:8000/devtools/network/resources/resource.php?jscontent=1
client 2: intercepted request to http://127.0.0.1:8000/devtools/network/resources/resource.php?jscontent=1
client 1: rejecting request to http://127.0.0.1:8000/devtools/network/resources/resource.php?jscontent=1
client 2: intercepted response 418 from http://127.0.0.1:8000/devtools/network/resources/resource.php?jscontent=1
-- failing request from client 3
client 3: failing request from http://127.0.0.1:8000/devtools/network/resources/resource.php