POC that shows how to subscribe to built-in diagnostics_channel events for the http module in Node.js - unfortunately there's no way of subscribing to error events. As of now, if the request fails after having started (i.e. `ECONNREFUSED`) the segment remains opened.

instrumentHttp.ts

import type { ClientRequest, IncomingMessage } from 'node:http';
import { subscribe } from 'node:diagnostics_channel';

public captureHTTPsGlobal(): void {
    const onRequestStart = (message: unknown): void => {
      const { request } = message as { request: ClientRequest };
      console.log(message);

      const parentSubsegment = this.getSegment();
      if (parentSubsegment && request.host) {
        const subsegment = parentSubsegment.addNewSubsegment(request.host);
        subsegment.addAttribute('namespace', 'remote');

        (subsegment as HttpSubsegment).http = {
          request: {
            url: request.host,
            method: request.method,
          },
        };

        this.setSegment(subsegment);
      }
    };

    const onResponseFinish = (message: unknown): void => {
      const { response } = message as { response: IncomingMessage };

      console.log(message);

      const subsegment = this.getSegment();
      if (isHttpSubsegment(subsegment)) {
        const status = response.statusCode || 0; // TODO: when can it be undefined?
        const contentLenght = response.headers['content-length'];

        subsegment.http = {
          ...subsegment.http,
          response: {
            status,
            ...(contentLenght && {
              content_length: parseInt(contentLenght),
            }),
          },
        };

        if (status === 429) {
          subsegment.addThrottleFlag();
        }
        if (status >= 400 && status < 500) {
          subsegment.addErrorFlag();
        } else if (status >= 500 && status < 600) {
          subsegment.addFaultFlag();
        }

        subsegment.close();
        this.setSegment(subsegment.parent);
      }
    };

    subscribe('http.client.request.start', onRequestStart);
    subscribe('http.client.response.finish', onResponseFinish);
  }