bytebuffer length calculation in TBinaryProtocol writeBinary

In TBinaryProtocol writeBinary, the length calculation appears incorrect:

length = bin.limit() - bin.position() - bin.arrayOffset();

This subtraction of arrayOffset can cause a negative length on a sliced buffer. For example:

ByteBuffer b = ByteBuffer.allocate(15);
b.put("1234567890".getBytes());

ByteBuffer b2 = b.slice();
b2.put("testx".getBytes());
b2.rewind();

So b2's length is lim-pos-offset = 5-0-10 = -5.

I believe we just want lim-pos.