async-git-prompt-status.ps1

#Thread-safe data structure to store prompt strings and communicate about state
$prompt = [Collections.Concurrent.ConcurrentDictionary[String,String]]@{}
$prompt.infix = ''

Set-PSReadlineOption -ExtraPromptLineCount 1 # For 2-line prompt
Register-EngineEvent -SourceIdentifier PowerShell.OnIdle -Action {
  if($prompt.state -eq 'rerender') {
    $prompt.isIdleRender = 'yes'
    [Microsoft.PowerShell.PSConsoleReadLine]::InvokePrompt()
    $prompt.isIdleRender = 'no'
  }
} | out-null

# Load multithreading library (https://github.com/cspotcodeMadMultithreading)
import-module 'C:\Users\abradley\Documents\Personal-dev\@TimCurwick\MadMultithreading\Supplemental.psm1'
Function __promptThreadInit {
  Import-Module posh-git
  $GitPromptSettings.AnsiConsole = $true
}
Function __promptThreadAction($prompt) {
  process {
    cd $_
    $prompt.infix = Write-VCSStatus
    $prompt.state = 'rerender'
  }
}
# Create persistent background thread to compute status
$promptThreadpool = New-MadThreadPool -Threads 1 -InitializeFunction (Get-Command __promptThreadInit)
Function Prompt {
  # If invoked via OnIdle event, refresh existing prompt, don't do a new one
  if($prompt.isIdleRender -eq 'yes') {
    $prompt.state = 'done'
    return $prompt.prefix + $prompt.infix + $prompt.suffix
  }
  # Compute prompt infix in background thread
  $prompt.state = 'waiting'
  Invoke-InMadThreadPool -Threadpool $promptThreadpool -function (Get-Command __promptThreadAction) -InputObject $PWD.Path -Parameters @{prompt = $prompt} -NoWaitForResults
  
  # Mostly-normal prompt logic.  Infix will carry over from previous prompt and be updated async via onidle event
  $prompt.prefix = $PWD.Path
  $prompt.suffix = "`n> "
  return $prompt.prefix + prompt.infix + $prompt.suffix
}