Summary:
Given that stream interceptor is async the folling race conditino could occur.
Frame at time t=0 comes in, we yeild to the event loop while fetching metadata, fetch takes 5 ticks
Frame at time t=1 comes in, we yeild to the event loop but fetch takes 1 tick
At time t=2 the second frame is augmented and display
At time t=5 the first fetch returns and we display and older frame
This is a simple check to avoid this.
Reviewed By: aigoncharov
Differential Revision: D45314013
fbshipit-source-id: 054e7e6beb52dfbfd94bc9f8ee3d0a758a669f66
862592e03d