CVE-2026-8927: flush the proxy Digest authentication state when the proxy
read from an environment variable differs from the one that state was
established for, so a Proxy-Authorization header computed for one proxy is
not sent to a different proxy on a reused handle
CVE-2026-8932: compare the client certificate type and the private key, its
type, password and blob when matching a connection for reuse and when
matching a cached TLS session, so a transfer cannot silently inherit another
handle's authenticated client identity