[Magisk] Gynoid:
Unfortunately it does not work on my OnePlus 5 (rooted and running latest LineageOS 15.1 + Magisk 17.1). Here is my log file:

*** tri-state-slider-override.op5: Sun Jan 31 23:15:23 GMT 1971
*
* Build Info
*
[ro.build.characteristics]: [nosdcard]
[ro.build.date]: [Mon Sep 10 11:52:12 UTC 2018]
[ro.build.date.utc]: [1536580332]
[ro.build.description]: [OnePlus5-user 8.1.0 OPM1.171019.011 1808081927 release-keys]
[ro.build.display.id]: [lineage_cheeseburger-userdebug 8.1.0 OPM6.171019.030.K1 167a26ef4b]
[ro.build.expect.firmware]: [5.1.5]
[ro.build.expect.modem]: [2018-08-08 20:13:54]
[ro.build.fingerprint]: [OnePlus/OnePlus5/OnePlus5:8.1.0/OPM1.171019.011/1808081927:user/release-keys]
[ro.build.flavor]: [lineage_cheeseburger-userdebug]
[ro.build.host]: [kallikrates.acc.umu.se]
[ro.build.id]: [OPM6.171019.030.K1]
[ro.build.product]: [OnePlus5]
[ro.build.selinux]: [1]
[ro.build.tags]: [release-keys]
[ro.build.type]: [userdebug]
[ro.build.user]: [jenkins]
[ro.build.version.all_codenames]: [REL]
[ro.build.version.base_os]: []
[ro.build.version.codename]: [REL]
[ro.build.version.incremental]: [167a26ef4b]
[ro.build.version.preview_sdk]: [0]
[ro.build.version.release]: [8.1.0]
[ro.build.version.sdk]: [27]
[ro.build.version.security_patch]: [2018-09-05]

*
* Sysfs Info
*
/sys/devices/virtual/switch:
total 0
drwxr-xr-x 6 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 .
drwxr-xr-x 48 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 ..
drwxr-xr-x 3 root root u:object_r:sysfs_graphics:s0 0 1971-02-01 00:15 hdmi
drwxr-xr-x 3 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 hdmi_audio
drwxr-xr-x 3 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 tri-state-key
drwxr-xr-x 3 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 wfd

/sys/devices/virtual/switch/tri-state-key:
total 0
drwxr-xr-x 3 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 .
drwxr-xr-x 6 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 ..
-r--r--r-- 1 root root u:object_r:sysfs:s0 4096 1971-02-01 00:15 name
drwxr-xr-x 2 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 power
-r--r--r-- 1 root root u:object_r:sysfs:s0 4096 1971-02-01 00:15 state
lrwxrwxrwx 1 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 subsystem -> ../../../../class/switch
-rw-r--r-- 1 root root u:object_r:sysfs:s0 4096 1971-02-01 00:15 uevent

*
* Processing
*
+ toybox ls -Zd /sys/devices/virtual/switch/tri-state-key
+ set -- u:object_r:sysfs:s0 /sys/devices/virtual/switch/tri-state-key
+ wanted_context=u:object_r:sysfs:s0
+ context_needed_change=0
+ context_changed=0
+ policy_change_attempted=0
+ policy_modified=0
+ policy_restored=0
+ toybox ls -Zd /sbin/.core/img/tri-state-slider-override.op5/empty
+ set -- u:object_r:system_file:s0 /sbin/.core/img/tri-state-slider-override.op5/empty
+ '[' u:object_r:system_file:s0 '!=' u:object_r:sysfs:s0 ]
+ context_needed_change=1
+ chcon u:object_r:sysfs:s0 /sbin/.core/img/tri-state-slider-override.op5/empty
chcon: '/sbin/.core/img/tri-state-slider-override.op5/empty' to u:object_r:sysfs:s0: Permission denied
+ policy_change_attempted=1
+ magiskpolicy --live 'allow sysfs labeledfs filesystem {associate}'
+ policy_modified=1
+ chcon u:object_r:sysfs:s0 /sbin/.core/img/tri-state-slider-override.op5/empty
+ context_changed=1
+ magiskpolicy --live 'deny sysfs labeledfs filesystem {associate}'
+ policy_restored=1
+ : 'context_needed_change=1' 'context_changed=1' 'policy_change_attempted=1' 'policy_modified=1' 'policy_restored=1'
+ mount --bind /sys/devices/virtual/switch/tri-state-key /sbin/.core/img/tri-state-slider-override.op5/sysfs
+ mount --make-private /sbin/.core/img/tri-state-slider-override.op5/sysfs
+ mount --bind /sbin/.core/img/tri-state-slider-override.op5/empty /sys/devices/virtual/switch/tri-state-key
+ toybox ls -laZ /sys/devices/virtual/switch /sys/devices/virtual/switch/tri-state-key /sbin/.core/img/tri-state-slider-override.op5/sysfs
/sbin/.core/img/tri-state-slider-override.op5/sysfs:
total 4
drwxr-xr-x 3 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 .
drwxr-xr-x 5 root root u:object_r:system_file:s0 4096 1971-02-01 00:15 ..
-r--r--r-- 1 root root u:object_r:sysfs:s0 4096 1971-02-01 00:15 name
drwxr-xr-x 2 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 power
-r--r--r-- 1 root root u:object_r:sysfs:s0 4096 1971-02-01 00:15 state
lrwxrwxrwx 1 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 subsystem -> ../../../../class/switch
-rw-r--r-- 1 root root u:object_r:sysfs:s0 4096 1971-02-01 00:15 uevent

/sys/devices/virtual/switch:
total 4
drwxr-xr-x 6 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 .
drwxr-xr-x 48 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 ..
drwxr-xr-x 3 root root u:object_r:sysfs_graphics:s0 0 1971-02-01 00:15 hdmi
drwxr-xr-x 3 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 hdmi_audio
drwxr-xr-x 2 root root u:object_r:sysfs:s0 4096 1971-02-01 00:15 tri-state-key
drwxr-xr-x 3 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 wfd

/sys/devices/virtual/switch/tri-state-key:
total 4
drwxr-xr-x 2 root root u:object_r:sysfs:s0 4096 1971-02-01 00:15 .
drwxr-xr-x 6 root root u:object_r:sysfs:s0 0 1971-02-01 00:15 ..
+ exit 0

I saw a "Permission denied". Is it not SELINUX-related?