OTEL tracing in driver

[IAmJSD]

Support for OpenTelemetry in the serverless driver for transactions/individual queries would be useful to allow for full tracing from request to response of all queries my application is performing

[nicksrandall]

I believe you could solve this with a custom fetchFunction, you'd just need to set it up like so:

import { neonConfig, neon } from `@neondatabase/serverless`
neonConfig.fetchFunction = async (url, init) => {
  // pull attrs of the the init object (like from the headers)
  const attrs = {};
  return currentTracer.startActiveSpan(`neon-query`, attrs,  async () => fetch(url, init));
}; 

[MatthewAry]

Has PR #102