Every field resolving against the settled layout — each index's page numbers, every
cross-reference — registers with scheduleFieldRound instead of taking a frame of its
own. A round measures for all of them before any of them writes, since a write between
two measurements lays the whole document out again, and their cached results ride one
transaction: a dispatch of its own costs a view update over the document, 55 ms per
index on a 460-page file. That file settles about 220 ms earlier, with every spacer,
page number and reference exactly where it was on five documents.
Steffen Becker
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