Parsing results after calling PowerShell Invoke-RestMethod

#to
see if this user is present in the user table
$Result  = Invoke-RestMethod -Credential $SNowCreds -Headers $headers
-Method Get -Uri ("https://" + $SNowInstance + ".
service-now.com/api/now/table/" + $Table + "sysparm_query=" + $AttribName +
"=" + $AttribValue)
return $Result.response.result.sys_id
#***How do we get the response code to make sure that the http call went
thro OK? If it is not 200, how can I retrieve the message that is returned
saying "constraint violation" etc..



#***If the http call is successful, check if we have exactly one record
retrieved - how do I do this?



}
catch
{
$Result = $_.Exception.Response.GetResponseStream()
        $Reader = New-Object System.IO.StreamReader($result)
        $ResponseBody = $Reader.ReadToEnd();
$message = "Unable to run a query on table" + $Table + "`tattribute name: "
+ $AttribName + "`tattribute value: " + $AttribValue + "`t" +
$_.Exception.Message + "`t" + $ResponseBody
writelog -msg ("ERROR `t" + $message)
return ""
}


thanks,
-Ravi