how to show divider between preference when merged to androidX-1.0.0/support-28

[BrightVan]

before support-28/androidX-1.0.0, there has divider between preference;
but now, only can show divider between PreferenceCategory;
i want to show divider between preference, and the divider line not match-parent,
it has a margin with the icon, like the below effect

------------------------
😇 title
   ---------------------
😇 title
   ---------------------
😇 title
   ---------------------
😇 title
------------------------

[BrightVan]

after read the source code, i find the way to add divider:

<Preference
            android:enabled="true"
            ....
            app:allowDividerAbove="true"
            app:allowDividerBelow="true"
           />

<Preference
            android:enabled="true"
            ....
            app:allowDividerAbove="true"
            app:allowDividerBelow="true"
           />

attention：both items should allowDivider if you want to show a divider between them.
and the first(last) preference item in a PreferenceCategory, you just need to set
app:allowDividerAbove="true/false" (app:allowDividerBelow="true/false") to control

but i am still do not know how to set a marginStart of a divider!