diagnostics_channel: add iterator support to tracing channel #4086

Job	Run time
Build slim tarball	1m 42s
x86_64-darwin: with shared libraries	27m 22s
aarch64-linux: with shared libraries	17m 51s
x86_64-linux: with shared libraries	20m 40s
aarch64-darwin: with shared libraries	22m 40s
	1h 30m 15s

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