local start
  start="$(date -u +%s.%N)"
  # First, get a trace and span ID. We need to get one now so we can propagate it to the child
  # Get trace ID from TRACEPARENT, if present
  local tid
  tid="$(<<<"${TRACEPARENT:-}" cut -d- -f2)"
  tid="${tid:-"$(tr -dc 'a-f0-9' < /dev/urandom | head -c 32)"}"
  # Always generate a new span ID
  local sid
  sid="$(tr -dc 'a-f0-9' < /dev/urandom | head -c 16)"