def trace(name, kvs = {}, &block)
      log_entry(name, kvs)
      result = block.call
      result
    rescue Exception => e
      log_error(e)
      raise
    ensure
      log_exit(name)
    end
def trace(name, kvs = {}, &block)
      log_entry(name, kvs)
      result = block.call
      result
    rescue Exception => e
      log_error(e)
      raise
    ensure
      log_exit(name)
    end
Trace a block of code within the context of the exiting trace

 Example usage:

 ::Instana.tracer.trace(:dbwork, { :db_name => @db.name }) do
   @db.select(1)
 end

 @param name [String] the name of the span to start
 @param kvs [Hash] list of key values to be reported in this new span