rmatio library is slower than R.matlab for importing

[moldach]

Hello,

I would like to report a speed difference between rmatio and R.matlab libraries. The rio package uses rmatio so it would be nice if the time to read a MATLAB matrice could be reduced:

> system.time(x <- R.matlab::readMat("http://ufldl.stanford.edu/housenumbers/test_32x32.mat"))
Registered S3 method overwritten by 'R.oo':
  method        from       
  throw.default R.methodsS3
   user  system elapsed 
   7.65    2.25   27.08 
> system.time(x <- rmatio::read.mat("http://ufldl.stanford.edu/housenumbers/test_32x32.mat"))
   user  system elapsed 
  34.54  109.36  161.91 
> system.time(x <- rio::import("http://ufldl.stanford.edu/housenumbers/test_32x32.mat"))
   user  system elapsed 
  97.75  131.48  308.01