Deffered evaluation for logs

deffer.ps1

# Logging verbose info to screen is useful for debugging
# but the info is hidden 99% of the time. Problem is that 
# evaluating a string to get the verbose message will run 
# even if we never actually print it, adding overhead to 
# every run, not just runs that are verbose. 

# to avoid this passing a script block that evaluates to the 
# message string conditionally seems to work well


# writes a string to screen
function v ([String]$m) {
    if ($writeToScreen) {
        Write-Host $m -NoNewline
    }
}

# adds optional delay that simulates
# some computation of info for the verbose message
function DoWork () {
    if ($delay -eq 0) {
    }
    elseif ($delay -eq 1) {
        $p = Get-Process -Id $PID
    }
    else {
        $i = Get-Process | Where { $_.Name -eq 'Idle' }
    }
}

# evaluates string from scriptblock and then 
# writes is to screen
function v2 ([ScriptBlock]$m) {
    if ($writeToScreen) {
        Write-Host (&$m) -NoNewline
    }
}

# does nothing but a function call
function v3 { }

# runs each function 1000 times 
# first with output to screen 
# (there most overhead is coming from
# Write-Host but the performance of functions
# that actually write to screen seem comparable
# with scriptblock being slightly slower

# in the second run nothing is written to the screen
# and there the scriptblock wins, by some 10ms

# it also adds a progresively long delay that shows how
# the overhead changes when some real work is done to produce
# the verbose message

# normal example from running this code: 
# write to screen: True, (delay 0): 1105.4102, 1239.677, 74.5671
# write to screen: False, (delay 0): 143.242, 89.707, 64.8482
# write to screen: True, (delay 1): 4093.0652, 4179.2973, 68.2799
# write to screen: False, (delay 1): 2480.0881, 86.4388, 65.0745
# write to screen: True, (delay 2): 11269.3723, 12252.0789, 66.3764
# write to screen: False, (delay 2): 9578.4522, 86.4895, 70.4621

# extreme example of a case where I output cimclass to the console
# write to screen: True, (delay 0): 1085.6265, 1154.473, 80.5295
# write to screen: False, (delay 0): 146.2093, 90.4551, 64.5146
# write to screen: True, (delay 1): 4192.0924, 4076.2387, 71.131
# write to screen: False, (delay 1): 2416.7699, 89.4839, 65.3627
# write to screen: True, (delay 2): 54331.3003, 53858.9505, 64.5398
# write to screen: False, (delay 2): 50871.7438, 90.6663, 66.7613

$name = "Jakub"

$r = 0,1,2 | foreach {
    $delay = $_ 
    $true, $false | foreach {
        $writeToScreen = $_
        $t1 = (Measure-Command { 
            1..1000 | % { v "Hello,$(doWork) $name"} 
        }).TotalMilliseconds

        $t2 = (Measure-Command  {
            1..1000 | % { v2 { "Hello,$(doWork) $name" } } 
        }).TotalMilliseconds

        $t3 = (Measure-Command  {
            1..1000 | % { v3 } 
        }).TotalMilliseconds

        "write to screen: $writeToScreen, (delay $delay): $t1, $t2, $t3"
    }
}

"`n"
$r