Use SerializeIter #946

Job	Run time
Examples	2m 0s
Build docs	20s
Test (macOS)	1m 17s
Check minimal versions	36s
MSRV	0s
Test (nightly)	1m 14s
Test (stable)	2m 30s
Test (beta)	2m 11s
Test (Windows)	3m 3s
Test (native-tls)	2m 17s
Test (no default features)	37s
Test (no cache)	2m 20s
Test (no gateway)	1m 40s
Test (unstable Discord API features)	2m 39s
Test (chrono, chrono)	37s
Test (unstable API + typesize, default unstable typesize, true)	52s
Test (builder without model, builder, true)	23s
Test (unstable Discord API (no default features), unstable, true)	18s
	24m 54s

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