lib-fs: ostream-metawrap shouldn't count metadata header as part of the stream offsets.
lib-fs: ostream-metawrap shouldn't count metadata header as part of the stream offsets.

jwm/dovecot-notmuch,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jwm/dovecot-notmuch