Add ability to handle async Ring requests (#19) * Making instrumentation async ready * Handling async requests on exposing metrics * Simplifying handler invocation * Handling sync exceptions for async handler * Adding note about async ring support. --------- Co-authored-by: Janos Meszaros <jmeszaros@whitepages.com> Co-authored-by: Janos Meszaros <jmeszaros@ekata.com>