Along the lines of the toString() caching in #22340, we can also cache the resolved Charset instance in MimeType, in particular for repeated getCharset() calls in if conditions (which are quite common in our converter implementations).
Along the lines of the toString() caching in #22340, we can also cache the resolved Charset instance in MimeType, in particular for repeated getCharset() calls in if conditions (which are quite common in our converter implementations).