Lasse R.H. Nielsen
0bd3dfa398
Was adding key to _keymap before calling `ifAbsent`, so `containsKey` saw it during the `ifAbsent` call. Modified to allow concurrent modification inthe `ifAbsent` function, like other platforms already do. Documentation updated to match. Fixes #47852 CoreLibraryReviewExempt: DDC only change, other than docs. Bug: https://dartbug.com/47852 Change-Id: Ia289f426b1c9ad37ce89eda5119f9086dc5d39b4 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/222200 Commit-Queue: Lasse Nielsen <lrn@google.com> Reviewed-by: Nate Biggs <natebiggs@google.com>