feat: support set max threads

[jim3ma]

Description

Related Issue

Motivation and Context

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.99%. Comparing base (c9180af) to head (8326d50).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3537      +/-   ##
==========================================
- Coverage   52.04%   51.99%   -0.05%     
==========================================
  Files         190      190              
  Lines       20434    20434              
==========================================
- Hits        10634    10625       -9     
- Misses       8994     9000       +6     
- Partials      806      809       +3     

Flag	Coverage Δ
unittests	51.99% <ø> (-0.05%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
client/config/peerhost.go	47.46% <ø> (ø)

... and 3 files with indirect coverage changes

[gaius-qi]

LGTM