[Centos] Process.io_counter().write_bytes get wrong data

[Zhangfredy]

Platform

• { Centos7.8.2003 }
• { psutil version: 5.4.7 }
• { 2.7.5 }

Bug description
...
The amount of change in Process.io_counters().write_bytes is greater than the amount of data written to sda in the same segment as iostat statistics. In a statistical time of 18 minutes, it is about 10 times the difference. The former data volume is 2000M, the latter 200M。The latter should be more practical. So how to get the correct write_bytes