Changes in 2.2.1:

• Add a Hashable instance for Async
• Bump upper bounds
• Documentation updates

Changes in 2.2:

• cancel now throws AsyncCancelled instead of ThreadKilled
• link and link2 now wrap exceptions in ExceptionInLinkedThread when throwing to the linked thread. ExceptionInLinkedThread is a child of AsyncException in the exception hierarchy, so this maintains the invariant that exceptions thrown asynchronously should be AsyncExceptions.
• link and link2 do not propagate AsyncCancelled, so it's now possible to cancel a linked thread without cancelling yourself.
• Added linkOnly and link2Only to specify which exceptions should be propagated,if you want something other than the default behaviour of ignoring AsyncCancelled.
• new utility function compareAsyncs for comparing Asyncs of different types.
• Add a Hashable instance for Async a

Changes in 2.1.1.1:

• Make 'cancelWith' wait for the cancelled thread to terminate, like 'cancel'
• Updates to dependency bounds for GHC 8.2

Changes in 2.1.1:

• Add concurrently_
• Add replicateConcurrently
• Add replicateConcurrently_
• Fix incorrect argument order in forConcurrently_
• Generalize mapConcurrently_ and forConcurrently_ to Foldable
• withAsync now reliably kills the thread, by using an uninterruptible cancel
• Make cancel wait for the thread to finish, and adjust 'concurrently' to match

Changes in 2.1.0:

• Bump base dependency to allow 4.10
• Remove invalid Monad instance for Concurrently
• Add Monoid and Semigroup instances for Concurrently
• Add forConcurrently (flipped version of mapConcurrently)
• Add STM version of all applicable IO functions: waitAnySTM, waitAnyCatchSTM, waitEitherSTM, waitEitherCatchSTM, waitEitherSTM_, and waitBothSTM.

Changes in 2.0.2:

• Add a Monad instance for Concurrently
• Bump base dependency to allow 4.9

Changes in 2.0.1.6:

• Add workaround to waitCatch for #14

Changes in 2.0.1.5:

• Bump base dependencies for GHC 7.8

Changes in 2.0.1.4:

• Bump base dependency of test suite

Changes in 2.0.1.3:

• Bump base dependency to allow 4.6

Changes in 2.0.1.2:

• Bump stm dependency to 2.4

Changes in 2.0.1.1:

• Safe Haskell support: Control.Concurrent.Async is now Trustworthy

Changes in 2.0.1.0:

• Added a Functor instance for Async
• Added asyncBound, asyncOn, asyncWithUnmask, asyncOnWithUnmask, withAsyncBound, withAsyncOn, withAsyncWithUnmask, withAsyncOnWithUnmask.
• Added mapConcurrently
• Added Concurrently (with Applicative and Alternative instances)