Use boost::container::vector and boost::unordered_flat_map as array_type and table_type.
boost::container::vector
boost::unordered_flat_map
array_type
table_type
Install boost, especially after 1.81.0 that supports unordered_flat_map.
unordered_flat_map
Then, build toml11 with -DTOML11_BUILD_EXAMPLES=ON
-DTOML11_BUILD_EXAMPLES=ON
$ cmake -B ./build/ -DTOML11_BUILD_EXAMPLES=ON