[do not merge] feat: Span streaming & new span API

[sentrivana]

Introduce a new tracing.start_span() with a streamlined signature to eventually replace the original sentry_sdk.start_span() and sentry_sdk.start_transaction() APIs:

import sentry_sdk

sentry_sdk.init(
    _experiments={"trace_lifecycle": "stream"},
)

with sentry_sdk.tracing.start_span(name="my_span"):
    ...

Additionally, introduce a new streaming mode (sentry_sdk.init(_experiments={"trace_lifecycle": "stream"})) that will send spans as they finish, rather than by transaction.

The new API MUST be used with the new streaming mode, and the old API MUST be used in the legacy non-streaming (static) mode.

Migration guide: Coming soon in #5318

TODOs

• Profiling
• ...

Notes

• The batcher for spans is a bit different from the logs and metrics batchers because it needs to batch by trace_id (we can't send spans from different traces in the same envelope).
• Chose to go with a new file and a new span class so that we can just remove the old Span and drop the new StreamedSpan in tracing.py as a replacement.

Release Plan

• There will be prereleases for internal testing.
• We'll release the new API in a minor version as opt-in.
• In the next major, we'll drop the legacy API, and optionally point the top-level sentry_sdk.start_span() to the new API.

Project

https://linear.app/getsentry/project/span-first-sdk-python-727da28dd037/overview

[github-actions]

Semver Impact of This PR

⚪ None (no version bump detected)

📋 Changelog Preview

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Entries from this PR are highlighted with a left border (blockquote style).

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New Features ✨

• feat(ai): add parse_data_uri function to parse a data URI by constantinius in #5311
• feat(asyncio): Add on-demand way to enable AsyncioIntegration by sentrivana in #5288
• feat(openai-agents): Inject propagation headers for HostedMCPTool by alexander-alderman-webb in #5297
• feat: Support array types for logs and metrics attributes by alexander-alderman-webb in #5314

Bug Fixes 🐛

• fix(ai): redact message parts content of type blob by constantinius in #5243
• fix(clickhouse): Guard against module shadowing by alexander-alderman-webb in #5250
• fix(gql): Revert signature change of patched gql.Client.execute by alexander-alderman-webb in #5289
• fix(grpc): Derive interception state from channel fields by alexander-alderman-webb in #5302
• fix(litellm): Guard against module shadowing by alexander-alderman-webb in #5249
• fix(pure-eval): Guard against module shadowing by alexander-alderman-webb in #5252
• fix(ray): Guard against module shadowing by alexander-alderman-webb in #5254
• fix(threading): Handle channels shadowing by sentrivana in #5299
• fix(typer): Guard against module shadowing by alexander-alderman-webb in #5253
• fix: Stop suppressing exception chains in AI integrations by alexander-alderman-webb in #5309
• fix: Send client reports for span recorder overflow by sentrivana in #5310

Documentation 📚

• docs(metrics): Remove experimental notice by alexander-alderman-webb in #5304
• docs: Update Python versions banner in README by sentrivana in #5287

Internal Changes 🔧

Release

• ci(release): Bump Craft version to fix issues by BYK in #5305
• ci(release): Switch from action-prepare-release to Craft by BYK in #5290

Other

• chore(gen_ai): add auto-enablement for google genai by shellmayr in #5295
• chore: Add type for metric units by sentrivana in #5312
• ci: Update tox and handle generic classifiers by sentrivana in #5306

Other

• [do not merge] feat: Span streaming & new span API by sentrivana in #5317

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