Investigate Moving Data Path to Java

[original-brownbear]

Running Avro through JRuby instead of Java comes with significant overhead.

Let's investigate moving the main data path of this plugin to pure Java and Java's Avro library.

[original-brownbear]

@suyograo @jsvd FYI :)

[jgregmac]

+1 for this enhancement.

Our organization has a great interest in this issue. The Ruby AVRO codec does not implement the AVRO specification correctly. I don't know if the Java codec works any better, but we were considering taking a stab at implementing a java_avro codec ourselves. Unfortunately, my team does not have a ton of programming expertise, so this will be challenging for us.