Figure out how to reduce spurious blocking errors

I absolutely love this:

[WARNING] A Cats Effect worker thread was detected to be in a blocked state (WAITING)
  at java.base/jdk.internal.misc.Unsafe.park(Native Method)
  at java.base/java.util.concurrent.locks.LockSupport.park(LockSupport.java:221)
  at java.base/java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:715)
  at java.base/java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:938)
  at java.base/java.util.concurrent.locks.ReentrantLock$Sync.lock(ReentrantLock.java:153)
  at java.base/java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:322)
  at java.base/jdk.internal.misc.InternalLock.lock(InternalLock.java:74)
  at java.base/java.io.PrintStream.writeln(PrintStream.java:823)
  at java.base/java.io.PrintStream.println(PrintStream.java:1167)
  at cats.effect.unsafe.WorkerThread.run(WorkerThread.scala:438)

Stare at that for a second and think about what it really means. At least we know the detector is working fairly well!

Start with the warning and stack trace in WorkerThread.scala:438, then trace how the Cats Effect worker-thread blocked-state detector classifies this WAITING state. Determine which legitimate blocking cases are producing spurious warnings, and define a change that reduces those warnings without hiding genuine blocking; the issue is done when the detector's behavior is covered by evidence or tests.