PowerShell + C# Elevate-Privileges Function Explained

Can anyone explain what this function written in PowerShell/C# is doing or why it's required? I use it take ownership of things programatically but would like to know what the C# code is doing.

function Elevate-Privileges {
param($Privilege)
$Definition = @"
using System;
using System.Runtime.InteropServices;

public class AdjPriv {
    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
        internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall, ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr rele);

    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
        internal static extern bool OpenProcessToken(IntPtr h, int acc, ref IntPtr phtok);

    [DllImport("advapi32.dll", SetLastError = true)]
        internal static extern bool LookupPrivilegeValue(string host, string name, ref long pluid);

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
        internal struct TokPriv1Luid {
            public int Count;
            public long Luid;
            public int Attr;
        }

    internal const int SE_PRIVILEGE_ENABLED = 0x00000002;
    internal const int TOKEN_QUERY = 0x00000008;
    internal const int TOKEN_ADJUST_PRIVILEGES = 0x00000020;

    public static bool EnablePrivilege(long processHandle, string privilege) {
        bool retVal;
        TokPriv1Luid tp;
        IntPtr hproc = new IntPtr(processHandle);
        IntPtr htok = IntPtr.Zero;
        retVal = OpenProcessToken(hproc, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, ref htok);
        tp.Count = 1;
        tp.Luid = 0;
        tp.Attr = SE_PRIVILEGE_ENABLED;
        retVal = LookupPrivilegeValue(null, privilege, ref tp.Luid);
        retVal = AdjustTokenPrivileges(htok, false, ref tp, 0, IntPtr.Zero, IntPtr.Zero);
        return retVal;
    }
}
"@
    $ProcessHandle = (Get-Process -id $pid).Handle
    $type = Add-Type $definition -PassThru
    $type[0]::EnablePrivilege($processHandle, $Privilege)
}