The HTML imports polyfill shouldn't be much slower than native, since native imports are also asynchronous, but block execution of subsequent scripts. Any (smal

The HTML imports polyfill shouldn't be much slower than native, since native imports are also asynchronous, but block execution of subsequent scripts. Any (small) slowdown would be from the browsers pre-scanner not knowing to optimistically load imports. This can be avoided completely by using the `vulcanize` tool which bundles all imports into one file.