defaultCompressibleTypes top-level constant
Content types worth compressing.
Text compresses; a JPEG does not. Spending CPU to make an already-compressed body 2% larger is the usual cost of a naive compressor, so the default list names what actually benefits.
Implementation
const defaultCompressibleTypes = <String>{
'application/json',
'application/javascript',
'application/xml',
'application/xhtml+xml',
'image/svg+xml',
'text/css',
'text/csv',
'text/event-stream',
'text/html',
'text/javascript',
'text/plain',
'text/xml',
};