Tokio v0.2.7

This release includes both bug fixes and incremental improvements across most of Tokio. The primary bug fixes are to Runtime configured with basic_scheduler and task::LocalSet.

Fixes

• potential deadlock when dropping basic_scheduler Runtime.
• calling spawn_blocking from within a spawn_blocking (#2006).
• storing a Runtime instance in a thread-local (#2011).
• miscellaneous documentation fixes.
• rt: fix Waker::will_wake to return true when tasks match (#2045).
• test-util: time::advance runs pending tasks before changing the time (#2059).

Added

• net::lookup_host maps a T: ToSocketAddrs to a stream of SocketAddrs (#1870).
• process::Child fields are made public to match std (#2014).
• impl Stream for sync::broadcast::Receiver (#2012).
• sync::RwLock provides an asynchonous read-write lock (#1699).
• runtime::Handle::current returns the handle for the current runtime (#2040).
• StreamExt::filter filters stream values according to a predicate (#2001).
• StreamExt::filter_map simultaneously filter and map stream values (#2001).
• StreamExt::try_next convenience for streams of Result<T, E> (#2005).
• StreamExt::take limits a stream to a specified number of values (#2025).
• StreamExt::take_while limits a stream based on a predicate (#2029).
• StreamExt::all tests if every element of the stream matches a predicate (#2035).
• StreamExt::any tests if any element of the stream matches a predicate (#2034).
• task::LocalSet.await runs spawned tasks until the set is idle (#1971).
• time::DelayQueue::len returns the number entries in the queue (#1755).
• expose runtime options from the #[tokio::main] and #[tokio::test] (#2022).