Extract the MS2 data from an mzXML nodeset
grabMzxmlMS2(xml_data, file_metadata, rtrange, incl_polarity)
A `data.table` with columns for retention time (rt), precursor m/z (premz), fragment m/z (fragmz), collision energy (voltage), and intensity (int).
An `xml2` nodeset, usually created by applying `read_xml` to an mzXML file.
Information about the file used to decode the binary arrays containing m/z and intensity information.
A vector of length 2 containing an upper and lower bound on retention times of interest. Providing a range here can speed up load times (although not enormously, as the entire file must still be read) and reduce the final object's size.
Boolean determining whether the polarity of the scan should be returned as a column in the table (positive mode = 1, negative mode = -1)