[Haystack Client Java]Span initialization in the java client is computationally inefficient and expensive

[ayansen]

Right now the java client uses AtomicReferences to construct a span which is inefficient. We need to clean up the span initialisation code and make it more efficient.

[ayansen]

here's the reference to the code in the client https://github.com/ExpediaDotCom/haystack-client-java/blob/master/core/src/main/java/com/expedia/www/haystack/client/Span.java