Filter HTTP headers as they pass through the gateway. The gateway applies filters after other transformations,
so any headers set or renamed must also be listed here when using an ALLOW type policy.
BLOCK drops any headers that are in the list of items, so it acts as an exclusion list. ALLOW
permits only the headers in the list and removes all others, so it acts as an inclusion list.
Filter HTTP headers as they pass through the gateway. The gateway applies filters after other transformations, so any headers set or renamed must also be listed here when using an ALLOW type policy.