SFTP: use variable sizes for get()
SFTP: use variable sizes for get()

paragonie-scott/phpseclib,thaigialai1987/phpseclib,paragonie-scott/phpseclib,splitice/phpseclib,phpseclib/phpseclib,creatuity/phpseclib,melya/phpseclib,terrafrost/phpseclib,kenichiii/phpseclib,splitice/phpseclib,danog/phpseclib,kenichiii/phpseclib,thaigialai1987/phpseclib,metaclassing/phpseclib,melya/phpseclib,danog/phpseclib,creatuity/phpseclib,metaclassing/phpseclib