Add back -WhatIf support to core methods until #254 is in.

GitHubCore.ps1

@@ -105,7 +105,7 @@ function Invoke-GHRestMethod
         This wraps Invoke-WebRequest as opposed to Invoke-RestMethod because we want access
         to the headers that are returned in the response, and Invoke-RestMethod drops those headers.
 #>
-    [CmdletBinding()]
+    [CmdletBinding(SupportsShouldProcess)]
     param(
         [Parameter(Mandatory)]
         [string] $UriFragment,
@@ -194,6 +194,11 @@ function Invoke-GHRestMethod
         $headers.Add("Content-Type", "application/json; charset=UTF-8")
     }
 
+    if (-not $PSCmdlet.ShouldProcess($url, "Invoke-WebRequest"))
+    {
+        return
+    }
+
     $originalSecurityProtocol = [Net.ServicePointManager]::SecurityProtocol
 
     try
@@ -527,7 +532,7 @@ function Invoke-GHRestMethodMultipleResult
         but the request happens in the foreground and there is no additional status
         shown to the user until a response is returned from the REST request.
 #>
-    [CmdletBinding()]
+    [CmdletBinding(SupportsShouldProcess)]
     [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSReviewUnusedParameter", "", Justification="One or more parameters (like NoStatus) are only referenced by helper methods which get access to it from the stack via Get-Variable -Scope 1.")]
     [OutputType([Object[]])]
     param(
@@ -552,6 +557,11 @@ function Invoke-GHRestMethodMultipleResult
         [switch] $NoStatus
     )
 
+    if (-not $PSCmdlet.ShouldProcess($UriFragment, "Invoke-GHRestMethod"))
+    {
+        return
+    }
+
     $AccessToken = Get-AccessToken -AccessToken $AccessToken
 
     $stopwatch = [System.Diagnostics.Stopwatch]::StartNew()

Telemetry.ps1

@@ -139,7 +139,7 @@ function Invoke-SendTelemetryEvent
         Invoke-* methods share a common base code.  Leaving this as-is to make this file
         easier to share out with other PowerShell projects.
 #>
-    [CmdletBinding()]
+    [CmdletBinding(SupportsShouldProcess)]
     param(
         [Parameter(Mandatory)]
         [PSCustomObject] $TelemetryEvent
@@ -153,6 +153,11 @@ function Invoke-SendTelemetryEvent
     $body = ConvertTo-Json -InputObject $TelemetryEvent -Depth $jsonConversionDepth -Compress
     $bodyAsBytes = [System.Text.Encoding]::UTF8.GetBytes($body)
 
+    if (-not $PSCmdlet.ShouldProcess($uri, "Invoke-WebRequest"))
+    {
+        return
+    }
+
     try
     {
         Write-Log -Message "Sending telemetry event data to $uri [Timeout = $(Get-GitHubConfiguration -Name WebRequestTimeoutSec))]" -Level Verbose