title: RAM prediction that will be allocated for the mixed models calculation
body: <p>Is it possible to at least approximately forecast the <code>RAM</code> capacity that will be needed to calculate the <code>mixed models</code> with <code>Julia</code>? (having information about the formula, dataset and server characteristics)
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  Of particular interest is the ability to predict the size of memory that will be needed for the fitting (<code>model = fit! (LinearMixedModel (formula, data), REML = true)</code>)</p>