inEventLoop
Returns true if the current NIOThread is the same as the NIOThread that is tied to this EventLoop. false otherwise.
var inEventLoop: Bool { get }This method is intended principally as an optimization point, allowing users to write code that can provide fast-paths when this property is true. It is not suitable as a correctness guard. Code must be correct if this value returns false even if the event loop context is actually held. That’s because this property is allowed to produce false-negatives
Implementers may implement this method in a way that may produce false-negatives: that is, this value may return false in cases where the code in question actually is executing on the event loop. It may never produce false positives: this value must never return true when event loop context is not actually held.
If it is necessary for correctness to confirm that you’re on an event loop, prefer preconditionInEventLoop(file:line:).