Returns a list with fields `fit` (the CmdStanMCMC/CmdStanVB), `par_vals` (named list of draws merged across chains), and `vb` (logical).
.hbayesdm_fit(
model_name,
data_list,
pars,
gen_init,
vb,
nchain,
niter,
nwarmup,
nthin,
adapt_delta,
stepsize,
max_treedepth,
ncore,
seed = 42,
inc_postpred = FALSE,
postpreds = NULL
)