Project Loom and JDK 20

[Alan Bateman]

The fork from main line for JDK 20 is scheduled for Dec 8. Here's a 
brief update on where this project is at:

Virtual Threads: We've submitted a JEP [1] to propose a second preview. 
No change in direction, no changes to APIs. There is a lot in this and 
keeping it as preview for a second release will allow time to get more 
experience with this feature.

Structured Concurrency: We've submitted a JEP [2] to propose to 
re-incubate the API for a second release. This API needs more feedback 
and real world usage. The API has been updated to support the 
inheritance of scoped values. To make things easy, the API changes are 
included in JEP 429.

JEP 429: Scoped values (Incubator) is currently a candidate. The PR and 
CSR for this feature are in flight. If all goes well then Andrew will 
propose to target it to 20. In the mean-time, there are EA builds [4] 
with the latest API.

-Alan

[1] https://openjdk.org/jeps/8295817
[2] https://openjdk.org/jeps/8296037
[3] https://openjdk.org/jeps/429
[4] https://jdk.java.net/loom/