mik3y/usb-serial-for-android — pull request #40 by nonmanifold (2013-11-18 07:27:29+00:00)
Title: Update FtdiSerialDriver.java

as of https://developer.android.com/reference/android/hardware/usb/UsbDeviceConnection.html#bulkTransfer(android.hardware.usb.UsbEndpoint, byte[], int, int)
bulkTransfer returns length of data transferred (or zero) for success, or negative value for failure