RFC 3546 has a number of new features, and we should consider them.  The
maximum fragment length is obvious.

suggested API in SSLEngine/SSLSocket

public int getPreferredBufferSize()
public void setPreferredBufferSize(int size)
When negotiating, implementation will try to negotiate a buffer size
of no larger than size bytes.  A value too small will be rounded up to 
the minimum supported buffer size.

From RFC, the currently supported numbers are, 2^14 and 2^x  x<=9<=12,
but we don't need to put that into the API.
 
So for example:

		x=2^16 would round down to 2^14
2^14
		x=10k would round down to 2^12 (4096)
2^12
...
2^9
		x=5 would round up to 2^9

This value will need to reflected in the SSLSession, when the SSLEngine changes
go in.

###@###.### 2003-07-18

This value should be set to the standard TLS/SSL size by default.