Simplify message visitor #1015

Job	Run time
Linux [UBSAN] [lmdb \| clang]	35m 18s
macOS [UBSAN] [lmdb \| clang]	31m 21s
Linux [ASAN] [lmdb \| clang]	31m 39s
macOS [ASAN] [lmdb \| clang]	24m 43s
Linux [ASAN_INT] [lmdb \| clang] (Errors Ignored)	23m 38s
macOS [TSAN] [lmdb \| clang] (Errors Ignored)	29m 29s
Linux [TSAN] [lmdb \| clang] (Errors Ignored)	35m 31s
macOS [UBSAN] [rocksdb \| clang]	37m 23s
Linux [LEAK] [lmdb \| clang] (Errors Ignored)	22m 27s
Linux [UBSAN] [rocksdb \| clang]	38m 52s
macOS [ASAN] [rocksdb \| clang]	27m 55s
Linux [ASAN] [rocksdb \| clang]	22m 34s
macOS [TSAN] [rocksdb \| clang] (Errors Ignored)	34m 33s
Linux [ASAN_INT] [rocksdb \| clang] (Errors Ignored)	32m 48s
Linux [TSAN] [rocksdb \| clang] (Errors Ignored)	15m 34s
Linux [LEAK] [rocksdb \| clang] (Errors Ignored)	24m 58s
	7h 48m 43s

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