Add Python SDK option to opt out of HTTP/2

[sarmientoF]

Summary

• Keep HTTP/2 as the Python SDK default.
• Add a public http2 connection option so callers can opt out with http2=False for API and envd transports.
• Thread the option through sync/async API clients and sandbox envd transport creation.
• Add tests for the default HTTP/2 behavior and the explicit HTTP/1.1 opt-out.

Why

For normal use, HTTP/2 remains the right default. The opt-out is for server-side high fan-out workloads where httpx uses one HTTP/2 connection per origin and therefore one server MAX_CONCURRENT_STREAMS budget. Once a workload has more long-lived concurrent envd RPCs than the peer stream cap, HTTP/2 requests queue behind that single connection instead of spreading across the existing connection pool.

http2=False gives those workloads a documented alternative: HTTP/1.1 uses the SDK/httpx connection pool and avoids coupling all concurrent envd RPCs to one HTTP/2 stream budget. This is useful for bash/filesystem/commands/pty/control-plane fan-out and does not change behavior for default users.

Reproduction / metrics

Using this branch and AsyncSandbox.commands.run, I ran 180 concurrent commands against one sandbox. Benchmark script: https://gist.github.com/sarmientoF/0d7db8c8f9cdaa154ab915088a238967

python /tmp/e2b_cloud_http2_repro.py \
  --env-file /Users/fernando-sarmiento/Desktop/jai/E2B/.env \
  --concurrency 180 \
  --sleep-seconds 4 \
  --request-timeout 45

Workload: sleep 4; echo ok, 180 concurrent server-streaming envd RPCs.

mode	ok/errors	elapsed	throughput	p50	p95	p99	max
HTTP/2 default	180/0	9.03s	19.94/s	4.82s	9.01s	9.01s	9.01s
HTTP/1.1 opt-out	180/0	5.20s	34.63/s	5.01s	5.16s	5.17s	5.18s

The HTTP/2 run completes in two waves because concurrency above the stream budget cannot use a second HTTP/2 connection. The HTTP/1.1 opt-out completes in one wave because requests are distributed through the connection pool.

Tests

• ./.venv/bin/pytest tests/test_api_client_transport.py tests/sync/sandbox_sync/test_config_propagation.py tests/async/sandbox_async/test_config_propagation.py
• ./.venv/bin/ruff check .
• ./.venv/bin/ruff format --check .
• ./.venv/bin/ty check

[changeset-bot]

🦋 Changeset detected

Latest commit: 11b2f2d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@e2b/python-sdk	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[mishushakov]

I will defer to @matthewlouisbrockman, but I don't think we should allow this - it would re-introduce the connection issues we've been trying to avoid by introducing http2.