feat: add Open.custom(source)

• Merge pull request ZJONSSON#229 from dergutehirte/master
• Merge pull request ZJONSSON#211 from mrbabbs/fix-default-concurrency-extract
• Merge pull request ZJONSSON#208 from george-norris-salesforce/patch-1
• Port changes from articulate#1

fix: add types definition file

v1.0.1

fix: add types definition file

feat!: add Azure Storage Blob adapter

BREAKING CHANGE: makes entry.stream() async, returning stream promise