Major - P3 Implement a string version for the int128 type so it can be logged easily.
Here's the error trace when you try to use an int128 with the LOGV2 macro:
In file included from src/mongo/logv2/log.h:36: In file included from src/mongo/logv2/log_debug.h:36: In file included from src/mongo/logv2/log_detail.h:37: src/mongo/logv2/attribute_storage.h:286:5: error: static_assert failed due to requirement 'hasToString<absl::int128> || hasToStringReturnStringData<absl::int128> || hasStringSerialize<absl::int128> || hasNonMemberToString<absl::int128> || hasNonMemberToStringReturnStringData<absl::int128> || hasBSONBuilderAppend<absl::int128> || hasBSONSerialize<absl::int128> || hasToBSON<absl::int128> || hasToBSONArray<absl::int128> || hasNonMemberToBSON<absl::int128>' "custom type needs toBSON(), toBSONArray(), serialize(BSONObjBuilder*), toString() or serialize(fmt::memory_buffer&) implementation" static_assert(hasToString<T> || hasToStringReturnStringData<T> || hasStringSerialize<T> || ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ src/mongo/logv2/attribute_storage.h:594:66: note: in instantiation of function template specialization 'mongo::logv2::detail::mapValue<absl::int128, 0>' requested here NamedAttribute(const char* n, const T& val) : name(n), value(mapValue(val)) {} ^ src/mongo/logv2/attribute_storage.h:622:17: note: in instantiation of function template specialization 'mongo::logv2::detail::NamedAttribute::NamedAttribute<absl::int128>' requested here : _data{detail::NamedAttribute(args.name, args.value)...} {} ^ src/mongo/logv2/attribute_storage.h:637:12: note: in instantiation of member function 'mongo::logv2::detail::AttributeStorage<mongo::logv2::detail::NamedArg<absl::int128>>::AttributeStorage' requested here return {args...}; ^ src/mongo/logv2/log_detail.h:76:23: note: in instantiation of function template specialization 'mongo::logv2::detail::makeAttributeStorage<mongo::logv2::detail::NamedArg<absl::int128>>' requested here auto attributes = makeAttributeStorage(args...); ^ src/mongo/logv2/log_detail.h:122:38: note: in instantiation of function template specialization 'mongo::logv2::detail::doLogUnpacked<FMT_COMPILE_STRING, absl::int128>' requested here auto&&... args) { doLogUnpacked(id, severity, options, formatMsg, args...); }, ^ src/mongo/bson/util/bsoncolumn_test.cpp:812:5: note: in instantiation of function template specialization 'mongo::logv2::detail::doLog<FMT_COMPILE_STRING, mongo::logv2::detail::NamedArg<absl::int128>>' requested here