Immediate first discovery

[FracturedShader]

Description

Waiting for the announcement period before the first announcement is surprising behavior, especially with longer intervals.

This commit changes the behavior so that the first announcement happens almost immediately and subsequent announcements are spaced by the provided period. This better matches user expectations of "connect as early as possible with periodic retry".

Contributor Checklist

• Commit messages follow the project guidelines.
• The code follows the style guidelines of this project.
• N/A: Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally. This is a slight re-ordering of events from Wait, Announce, Wait, Announce to Announce, Wait, Announce, Wait
• N/A: Any new/modified methods have been properly documented using Doxygen. This is a slight re-ordering of events from Wait, Announce, Wait, Announce to Announce, Wait, Announce, Wait
• N/A: Any new configuration API has an equivalent XML API (with the corresponding XSD extension). No new configuration.
• Changes are backport compatible: they do NOT break ABI nor change library core behavior. This does change core behavior. Some users may depend (improperly) on the internal timing.
• Changes are API compatible.
• New feature has been added to the versions.md file (if applicable). Unsure if this is really a new feature, a hotfix, or something else.
• New feature has been documented/Current behavior is correctly described in the documentation. Unsure if this is really a new feature, a hotfix, or something else.
• Applicable backports have been included in the description. Unsure if this is backport friendly.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• If this is a critical bug fix, backports to the critical-only supported branches have been requested.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.