# This PR
Change the trace request limit from 2 MiB to 50 MiB.

# Motivation
When the Node.js tracer layer sends a request to Lambda extension that's
between 2 MiB and 50 MiB, the extension closes the HTTP connection, the
tracer gets an `EPIPE` error and breaks. (Maybe the tracer should handle
the error better, but that's out of scope of this PR.)

According to @rochdev:
> the agent is supposed to have a limit of 50mb

So let's change the limit on agent side to match the expectation.

# Testing
Tested with Node.js 22 Lambda with this handler:
```
import tracer from 'dd-trace';
import crypto from 'crypto';
tracer.init();

function randomGarbage(len) {
  // low-compressibility payload (random bytes -> base64)
  return crypto.randomBytes(len).toString('base64');
}

export const handler = async (event) => {
  const SPANS = 3000;
  const TAG_BYTES_PER_SPAN = 20_000; // ~20 KB per span tag (base64 expands a bit)

  const root = tracer.startSpan('repro.root');
  root.setTag('dd.repro', 'true');

  for (let i = 0; i < SPANS; i++) {
    console.log(`Sending the ${i}-th span`);
    const span = tracer.startSpan('repro.child', { childOf: root });
    span.setTag('blob', randomGarbage(TAG_BYTES_PER_SPAN));
    span.finish();
  }
  root.finish();

  const response = {
    statusCode: 200,
    body: JSON.stringify('Hello from Lambda!'),
  };
  return response;
};
```

### Before:
There are errors like:
```
Error: write EPIPE
at WriteWrap.onWriteComplete [as oncomplete] (node:internal/stream_base_commons:95:16)
at WriteWrap.callbackTrampoline (node:internal/async_hooks:130:17)
```
```
LAMBDA_RUNTIME Failed to post handler success response. Http response code: 403. {"errorMessage":"State transition from Ready to InvocationErrorResponse failed for runtime. Error: State transition is not allowed","errorType":"InvalidStateTransition"}
```

### After
When Lambda's memory is 1024 MB, the error no longer happens.
When Lambda's memory is 512 MB, the invocation can fail due to OOM. But
I think that's a legit error. We can ask customers to increase memory
limit for high-volume workload like this.

# Notes
cc @astuyve who set a `MAX_CONTENT_LENGTH` of 10 MiB in
#294. This PR
increases it to 50 MiB as well.

Thanks @dougqh @duncanista @lucaspimentel @rochdev for discussion.

#899
Jira: https://datadoghq.atlassian.net/browse/SVLS-7777

* wip: tracing

* feat: tracing WIP

* feat: rename mini agent to trace agent

* feat: fmt

* feat: Fix formatting after rename

* fix: remove extra tokio task

* feat: allow tracing

* feat: working v5 traces

* feat: Update to use my branch of libdatadog so we have v5 support

* feat: Update w/ libdatadog to pass trace encoding version

* feat: update w/ merged libdatadog changes

* feat: Refactor trace agent, reduce code duplication, enum for trace version. Pass trace provider. Manual stats flushing. Custom create endpoint until we clean up that code in libdatadog.

* feat: Unify config, remove trace config. Tests pass

* feat: fmt

* feat: fmt

* clippy fixes

* parse time

* feat: clippy again

* feat: revert dockerfile

* feat: no-default-features

* feat: Remove utils, take only what we need

* feat: fmt moves the import

* feat: replace info with debug. Replace log with tracing lib

* feat: more debug

* feat: Remove call to trace utils