Shade Netty to simplify dependency conflicts against other systems

[imasahiro]

A user want to use Armeria on Netty 4.0 based system (e.g. Apache Flink uses Netty 4.0) but because Armeria uses methods that is newly added in Netty 4.1, it causes NoSuchMethodException at runtime.

To solve this, he/she can relocate Netty4.1 by himself/herself.
But I think, it would be nice if we provide an armeria library that shade Netty dependency.

/cc @okdtsk

[arkadius]

I would also like to use armeria with flink. I've already prepared change with this relocations: https://github.com/arkadius/armeria/tree/netty-shaded. Should I create PR or this change is someway controversial?

[trustin]

@arkadius Good start, but we'd also need to:

• Hide Netty classes from our public API, e.g. EventLoop, AsciiString and AttributeMap
• Make sure tcnative and epoll works even after shading.

Are you interested in making this change? It will be mostly about:

• Replace AsciiString with String or something else
• Fork AttributeMap
• Wrap EventLoop with Armeria's own EventLoop interface

[arkadius]

Yes, I'm interested in making this change. I'll analyse your proposal and will try to add this improvements.

[trustin]

@arkadius Awesome! Please feel free to let us know if you have any questions or need any help.

[trustin]

Closing. See #1168 for more information.