GitLab

Fixes #10271

The number of off-screen pages was too small, resulting in the
possibility of you still being offscreen after the pages loaded,
which could lead to loading more data, which could lead to you still
being offscreen, ad infinitum.

Simply increasing the number of buffer
pages resolves it.

Tested by adding an artificial 1 second delay to
loading a page.

Co-authored-by: Alan Evans <alan@signal.org>