[ci skip] use static_cast avoid warnings
[ci skip] use static_cast avoid warnings

chdinh/mne-cpp,chdinh/mne-cpp,LorenzE/mne-cpp,LorenzE/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,mne-tools/mne-cpp,mne-tools/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,LorenzE/mne-cpp,mne-tools/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,chdinh/mne-cpp,LorenzE/mne-cpp