Now that we have a system for storing HTTP headers for each integration, we
should fix the send_all button. Previously, it used the same user entered
custom HTTP header (from the GUI) for all of the fixtures, but now we
automatically determine the header with the new system instead.
Now that we store HTTP headers in a way that is easy to retreive
by specifying the integration name and fixture name, we should
use it to pre-load the "Custom HTTP Headers" field in the
integrations dev panel.
Hemanth V. Alluri