diagnostics_channel: add BoundedChannel and scopes #4343

Job	Run time
Build slim tarball	1m 43s
aarch64-linux: with shared libraries	17m 55s
x86_64-darwin: with shared libraries	32m 30s
x86_64-linux: with shared libraries	21m 34s
aarch64-darwin: with shared libraries	20m 44s
aarch64-linux: with shared libraries	16m 30s
x86_64-linux: with shared libraries	21m 34s
aarch64-darwin: with shared libraries	20m 44s
x86_64-darwin: with shared libraries	32m 30s
Build slim tarball	1m 43s
x86_64-linux: with shared libraries	19m 37s
aarch64-linux: with shared libraries	16m 59s
aarch64-darwin: with shared libraries	20m 32s
Build slim tarball	1m 43s
x86_64-darwin: with shared libraries	34m 58s
	4h 41m 16s

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