Mounting a remote network directory shared by sshfs to docker containers in WSL

Let's say I am running a docker container in WSL and a remote source directory is mounted to a WSL target directory by sshfs. And I want to mount the sshfs shared folder to the docker container.

When I first tried this, I used the following command to mount the remote source directory 

sshfs <remote server name>:<source directory in the server>  <target directory in WSL>

and ran docker image as if sshfs shared directory is just a local directory.

docker run  -v  <target directory in WSL>:<target directory in docker container> <docker image name>

But in this case, target directory in docker container was empty without any error message.

So I searched through the google about this problem and the suggested solution was 

 https://serverfault.com/questions/947182/mount-a-sshfs-volume-into-a-docker-instance

However, it didn't work either.

Fortunately, with some trial and error, I found out that I need to use '-o idmap=user' option with the above sshfs command. So, it becomes

sshfs -o allow_other -o idmap=user remote_server_name:<source directory> <target_directory>

And it works fine. 

I still don't know if this is a wsl specific problem or it generally happens in linux environments.