[R-meta] multivariate fixed-effect meta-analysis

Hi!
I'm performing a multivariate meta-analysis with metafor, however I'm
not sure how to obtain the fixed-effect version. Given that I have not
enough data I'm not interested in estimating tau for each outcome and
the correlation among outcomes but only taking into account the
sampling error dependence. I'm using this function:
```
rma.mv(
    yi = eff_size,
    V = cov_mat,
    mods = ~ 0 + outcome,
    struct = "UN",
    random = ~ outcome|paper_id,
    method = "FE",
    data = data)
```
Of course, the struct argument is no more relevant (as the warning
message said) but I'm wondering if the result is what I'm looking for
because from the rma.mv documentation the method = "FE" is not
mentioned combined with a multivariate parametrization.
Thank you!

Filippo Gambarota
PhD Student - University of Padova
Department of Developmental and Social Psychology
Website: filippogambarota.netlify.app
Research Group: Colab   Psicostat