[slurm-users] Make a job pending in the plugin

Hello all, I am tyring to build a custom plugin to force some jobs to be pended. In the official document, `ESLURM*` errors are only valid for `job_submit_lua`. I tried to send `ESLURM_JOB_PENDING`, but it only rejects the job submission. Does anyone know how to pend a job in job_submit plugin? Thanks.