Draw calls submitted. One per drawArrays-family call.
Primitive-set instances submitted. A non-instanced draw contributes 1
(GL's own model: drawArrays is drawArraysInstanced with one instance),
an instanced draw contributes its instance count.
Triangles submitted — per-instance triangle count times instance count, so
an instanced draw contributes all of its triangles. A "lines" geometry
contributes none.
What a backend submitted, accumulated since the last resetRenderStatistics.
Mutable and written in place; a backend never allocates one. The three fields are §84's, with §84's meanings — see FrameStats, which is where they surface as
app.stats.