feat(trace): span streaming, filtering, and exporting (#1235)

* wip

* clean up

* clean up

* clean up

* clean up

* clean up

* clean up

* wip

* fix black in pre-commit

* clean up

* remove proto codegen

* fix proto codegen

* remove proto script

* fix typo

* clean up

* clean up

* clean up

* clean up

* clean up

* clean up

* clean up

* clean up

* add lock to prevent KeyError exception

* fix type check

* fix test flakiness

* clean up

* clean up

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Co-authored-by: Xander Song <axiomofjoy@gmail.com>