On windows,
when use the config option 'innodb_flush_method=async_unbuffered'
it crashed as below.
But
innodb_flush_method=O_DIRECT is okay.

Question is that
what innodb_flush_method=O_DIRECT does it mean? fsync?
--------------------
2023-01-29 20:50:42 0x443c InnoDB: Assertion failure in file D:\winx64-packages\build\src\extra\mariabackup\xtrabackup.cc line 1909
InnoDB: Failing assertion: srv_file_flush_method <= IF_WIN(SRV_ALL_O_DIRECT_FSYNC, SRV_O_DIRECT_NO_FSYNC)
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to https://jira.mariadb.org/
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mariadbd startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: https://mariadb.com/kb/en/library/innodb-recovery-modes/
InnoDB: about forcing recovery.
230129 20:50:42 [ERROR] mysqld got exception 0x80000003 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.

To report this bug, see https://mariadb.com/kb/en/reporting-bugs

We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.

Server version: 10.7.7-MariaDB
key_buffer_size=0
read_buffer_size=131072
max_used_connections=0
max_threads=1
thread_count=0
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 5521 K bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
mariabackup.exe!???
ucrtbase.dll!raise()
ucrtbase.dll!abort()
mariabackup.exe!???
mariabackup.exe!???
mariabackup.exe!???
mariabackup.exe!???
mariabackup.exe!???
mariabackup.exe!???
KERNEL32.DLL!BaseThreadInitThunk()
ntdll.dll!RtlUserThreadStart()
The manual page at https://mariadb.com/kb/en/how-to-produce-a-full-stack-trace-for-mysqld/ contains
information that should help you find out what is causing the crash.

error code - "-2147483645"