Refactor renders (#15175)
* Refactor renders
* Some performance optimization
* Fix comment
* Transform reader
* Fix csv test
* Fix test
* Fix tests
* Improve optimaziation
* Fix test
* Fix test
* Detect file encoding with reader
* Improve optimaziation
* reduce memory usage
* improve code
* fix build
* Fix test
* Fix for go1.15
* Fix render
* Fix comment
* Fix lint
* Fix test
* Don't use NormalEOF when unnecessary
* revert change on util.go
* Apply suggestions from code review
Co-authored-by: zeripath <art27@cantab.net>
* rename function
* Take NormalEOF back
Co-authored-by: zeripath <art27@cantab.net>
9d99f6ab19