* Enable ModifierOrderCheck Checkstyle rule
* Fix violations for `static` and `abstract` modifier
* Remove redundant code in the `TcpNioConnection`
* Mark `connectionFactoryName` as `@Nullable` in the `TcpConnectionSupport`
ctor and its inheritors
* Fix some smells according IDEA suggestions in the affected classes
* This should fix some Sonar smells as well
* * Fix `HeaderMapperTests`
* * Polishing `TcpConnection` code style and fix Javdocs
93d7c58b64