XML support

[ugorji]

go-codec currently supports

• Binary: Msgpack
• Binary: CBOR
• Text: JSON

For completeness, it should support XML also.

Though XML has fallen out-of-favor, it is still widely used. The encoding/xml in the standard library is not efficient, and does not conform to the simplicity used in encoding/json. We have a chance to add a performant XML encoder/decoder as just another format.

We are attempting this due to perceived issues with encoding/xml:

• Complicated. It tried to do too much, and is not as simple to use as json.
• Due to over-engineering, reflection is over-used AND performance suffers:
  java is 6X faster:http://fabsk.eu/blog/category/informatique/dev/golang/
  even PYTHON performs better: http://outgoing.typepad.com/outgoing/2014/07/exploring-golang.html

codec framework will offer the following benefits

• VASTLY improved performance (when using reflection-mode or codecgen)
• simplicity and consistency: with the rest of the supported formats
• all other benefits of codec framework (streaming, codegeneration, etc)

go-codec is not a drop-in replacement for encoding/xml, as the tags and style will not transfer over.
Having said that, it is a replacement, based on the simplicity and performance of codec.

The goal is for this to be like JAXB for Go.

[2opremio]

+1. This could get us up to a 7% speedup in the Scope probes without making any investments since we are already using your library and codecgen.