#827: Use short form imports in pubsub docs

* build: use multiScm for Kokoro release builds

Source-Link: googleapis/synthtool@0da1658
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:5cddfe2fb5019bbf78335bc55f15bc13e18354a56b3ff46e1834f8e540807f05

* add constraints file for python 3.13

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Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Linchin <lingqing.gan@gmail.com>

…844)

Source-Link: googleapis/synthtool@395d53a
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:6c1cbc75c74b8bdd71dada2fa1677e9d6d78a889e9a70ee75b93d1d0543f96e1

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Source-Link: googleapis/synthtool@16790a3
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:543e209e7c1c1ffe720eb4db1a3f045a75099304fb19aa11a47dc717b8aae2a9

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Victor Chudnovsky <vchudnov@google.com>

Source-Link: googleapis/synthtool@6ed3a83
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:3abfa0f1886adaf0b83f07cb117b24a639ea1cb9cffe56d43280b977033563eb

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

…ads as a preview feature (#844)

* checkpoint before design doc impl

* checkpoint

* more tests

* code and tests for transfer manager complete

* proactively close temp files when finished reading

* respond to comments; destroy tmp files as they are consumed

* Add system tests, docstrings, address feedback

* Respond to review comments

* verify md5 hash of downloaded file in test

* lint

* default empty strings for root arguments

* fix bug with blob constructor

* add warning about files not being deleted if their downloads fail

…d downloads as a preview feature (#844)" (#897)

This reverts commit 9dcc6846b52e460bee8d725099abd4dc734fa7ad.