class ElasticAPM::OpenTracing::Tracer

def start_span(
  operation_name,
  child_of: nil,
  references: nil,
  start_time: Time.now,
  labels: {},
  ignore_active_scope: false,
  **
)
  span_context = prepare_span_context(
    child_of: child_of,
    references: references,
    ignore_active_scope: ignore_active_scope
  )
  if span_context
    trace_context =
      span_context &&
      span_context.respond_to?(:trace_context) &&
      span_context.trace_context
  end
  elastic_span =
    if ElasticAPM.current_transaction
      ElasticAPM.start_span(
        operation_name,
        trace_context: trace_context
      )
    else
      ElasticAPM.start_transaction(
        operation_name,
        trace_context: trace_context
      )
    end
  # if no Elastic APM agent is running or transaction not sampled
  unless elastic_span
    return ::OpenTracing::Span::NOOP_INSTANCE
  end
  span_context ||=
    SpanContext.from_trace_context(elastic_span.trace_context)
  labels.each do |key, value|
    elastic_span.context.labels[key] = value
  end
  elastic_span.start Util.micros(start_time)
  Span.new(elastic_span, span_context)
end