def write(self, f, time_start, time_stop, start, stop, step, samples, pwr_array):
        """Write data to file-like object"""
        f.write(self.magic)
        f.write(self.header_struct.pack(
            self.version, time_start, time_stop, start, stop, step, samples, pwr_array.nbytes
        ))
        #pwr_array.tofile(f)
        f.write(pwr_array.tobytes())
        f.flush()
Write data to file-like object