Usage of UpgradeToWriteLockAsync

[oruchreis]

Hi,
I'm trying to upgrade lock after read lock held, but UpgradeToWriteLockAsync method waits infinite. I've tried this script in roslynpad:

#r "nuget: DotNext.Threading, 5.4.0"
#r "nuget: DotNext, 5.3.1"
using System.Threading;
using DotNext.Threading;

await using var rwlock = new AsyncReaderWriterLock();

await Parallel.ForAsync(0,50, async (i,t)=>{
    using (await rwlock.AcquireReadLockAsync(t))
    {
        i.Dump();
        Thread.Sleep(i*10);
        rwlock.IsReadLockHeld.Dump("read");
        await rwlock.UpgradeToWriteLockAsync(t); //waits infinite
        try {
            rwlock.IsWriteLockHeld.Dump("write");
            Thread.Sleep(i*10);
        }
        finally {
            rwlock.DowngradeFromWriteLock();
        }
    }
    
});

[sakno]

Write lock is exclusive lock. Each async flow has acquired read lock. You cannot upgrade to write lock while you have active read locks.