This release adds experimental support for recording structured field values
using the valuable crate. See this blog post for details on
valuable.

Note that valuable support currently requires --cfg tracing_unstable. See
the documentation for details.

Added

• field: Experimental support for recording field values using the
  valuable crate (#1608, #1888, #1887)
• field: Added ValueSet::record method (#1823)
• subscriber: Default impl for NoSubscriber (#1785)
• metadata: New Kind::HINT to support the enabled! macro in tracing
  (#1883, #1891)

Fixed

• Fixed a number of documentation issues (#1665, #1692, #1737)

Thanks to @xd009642, @Skepfyr, @guswynn, @Folyd, and @mbergkvist for
contributing to this release!