3. Unicode: It replaces invalid utf8 with unicode questions marks (dunno how exactly is the replacement character called) but does not provide any API to detect that it happened. So that can lead to silent corruption of the data.
I think it’s well demonstrated to be slow (ns/op) and wasteful (allocs/op) in benchmarks, especially in bigger payloads.
The HTTP library is similar.
Most 3rd party libs make some trade offs that are pretty reasonable to achieve superior perf, but it’s worth understanding them to make sure it’s best for your use case.