A TCP sender calls sendall() twice with two application messages. What may the receiver o…

A TCP sender calls sendall() twice with two application messages. What may the receiver observe?

1. Exactly two recv() results with the same boundaries
2. One combined read, several partial reads, or other splits that preserve byte order
3. The two messages in reverse order when the network is congested
4. Only the second message because TCP overwrites its send buffer