bug: `(*Conn).Handshake()` is called upon `(*UConn).Read()` about utls

[guysv]

but basically if you explicitly call UConn.Handshake before UConn.Read you're good right?

[gaukas]

This behavior is not restricted to Read(), but also multiple other functions where UConn directly inherits from Conn.

[gaukas]

but basically if you explicitly call UConn.Handshake before UConn.Read you're good right?

Correct. This issue is more about an inconsistent behavior that when someone switch from crypto/tls to uTLS, where the former does not require an explicit call to Handshake, uTLS may use the default version of handshake if Handshake() is not explicitly called.