Add metrics from gopsutil v3 #7
Description
process_virtual_memory_bytes (proc.MemoryInfo().VMS)
process_swap_memory_bytes (proc.MemoryInfo().Swap)
CPU?
process_open_fds (proc.NumFDs())
process_io_bytes_total (proc.IOCounters().ReadBytes / proc.IOCounters().WriteBytes)
process_num_threads (proc.NumThreads())