fix: Serial connections race condition

[sansmoraxz]

Ensure devices registered on serial share the same client

Fixes: #685

If your build fails due to your commit message not passing the build checks, please review the guidelines here: https://github.com/edgexfoundry/device-modbus-go/blob/main/.github/Contributing.md

PR Checklist

Please check if your PR fulfills the following requirements:

• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• I am not introducing a new dependency (add notes below if you are)
• I have added unit tests for the new feature or bug fix (if not, why?)
• I have fully tested (add details below) this the new feature or bug fix (if not, why?)
• I have opened a PR for the related docs change (if not, why?) NA

Testing Instructions

Test cases. And against real hardware on same serial port.

New Dependency Instructions (If applicable)

NA

[codecov-commenter]

Codecov Report

❌ Patch coverage is 14.28571% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.26%. Comparing base (81a5ed9) to head (a5f73a6).

Files with missing lines	Patch %	Lines
internal/driver/modbusclient.go	0.00%	8 Missing ⚠️
internal/driver/driver.go	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #693      +/-   ##
==========================================
- Coverage   45.80%   45.26%   -0.55%     
==========================================
  Files           7        7              
  Lines         834      844      +10     
==========================================
  Hits          382      382              
- Misses        400      410      +10     
  Partials       52       52              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[sansmoraxz]

We should not be mixing baude rates, partity etc on the same port. Perhaps there can be a QOL improvement to bubble this up to the user when they are registering devices.

[weichou1229]

@sansmoraxz Do you think the serial connection should be locked? Because the Modbus usually doesn't support multiple threads, the driver locks the command by address as shown below:

device-modbus-go/internal/driver/driver.go

Lines 112 to 119 in ba3804a

	func (d *Driver) lockableAddress(info *ConnectionInfo) string {
	var address string
	if info.Protocol == ProtocolTCP {
	address = fmt.Sprintf("%s:%d", info.Address, info.Port)
	} else {
	address = info.Address
	}
	return address

[sansmoraxz]

It's quite odd, even with the above semaphore we were facing timeout issues with multiple devices.
^ Linked PR.

Not entirely sure what was happening then, might need to investigate more.