Merge "Update docs for RttCall#write" am: 730f35321d am: ef378a0df4 am: 021daefce0 am: 60b95316bf

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1480257

Change-Id: I19b50e045af5fd2efe7ca84474ea9d40dd0f5aff