elastic_fleet_load_integrations_dir now buffers each concurrent job's
output (header + API response) to a per-job file and prints them in
submission order after wait, restoring the readable serial-style output
while keeping concurrent writes.
Add --retry-all-errors to the integration create/update curl calls so
transient 409 conflicts from concurrent writes to the same agent policy
are retried (curl --retry alone does not retry 409).
Josh Patterson
d0bea2ebcb