Custom FB_FileLoad to compare with original one and performance measurement

Tc3_CustomFileLoad.cs

PROGRAM MAIN
VAR_INPUT
    pReadBuf: PVOID;
    sPathName: STRING;
END_VAR
VAR
    START: BOOL;
    READ_AT_ONCE: UDINT := 65536;
    
    Open:  FB_FileOpen;
    Read:  FB_FileRead;
    Close: FB_FileClose;

    state: INT;
    pCurrent: PVOID;
    timeCounter: UDINT;
END_VAR

IF state >= 100 AND state <= 300 THEN
    timeCounter := timeCounter + 1;
END_IF

CASE state OF
0:
    IF START THEN
        START := FALSE;
        timeCounter := 0;
        pCurrent := pReadBuf;
        state := 100;
    END_IF

100:
    Open(
        sNetId:= '', 
        sPathName:= sPathName, 
        nMode:= FOPEN_MODEREAD OR FOPEN_MODEBINARY, 
        ePath:= PATH_GENERIC, 
        bExecute:= TRUE
    );
    
    IF NOT open.bBusy THEN
        Open(bExecute:= FALSE);
        state := 200;
    END_IF
    
200:
    Read(
        sNetId:= '', 
        hFile:= Open.hFile, 
        pReadBuff:= pCurrent, 
        cbReadLen:= READ_AT_ONCE, 
        bExecute:= TRUE
    );

    IF NOT Read.bBusy THEN
        Read(bExecute:= FALSE);

        IF Read.cbRead > 0 THEN
            pCurrent := pCurrent + Read.cbRead;
        ELSE
            state := 300;
        END_IF    
    END_IF

300:
    Close(
        sNetId:= '', 
        hFile:= Open.hFile, 
        bExecute:= TRUE
    );
    
    IF NOT Close.bBusy THEN
        Close(bExecute:= FALSE);
        state := 0;
    END_IF
END_CASE

END_PROGRAM