shouldSignHeader

A predicate to control which headers are a part of the canonical request. Note that skipping auth-required headers will result in an unusable signature. Headers injected by the signing process cannot be skipped.

This function does not override the internal check function (e.g., for x-amzn-trace-id, user-agent, etc.) but rather supplements it. In particular, a header will get signed if and only if it returns true to both the internal check and this function (if defined).

The default predicate is to not reject signing any headers (i.e., _ -> true).