Behavior difference for walsender and walreceiver for n/w breakdown case

I have observed that currently incase there is a network break between
master and standby, walsender process gets terminated immediately, however
walreceiver detects the breakage after long time.

I could see that there is replication_timeout configuration parameter,
walsender checks for replication_timeout and exits after that timeout.

Shouldn't for walreceiver, there be a mechanism so that it can detect n/w
failure sooner?

Basic Steps to observe above behavior
1. Both master and standby machine are connected normally,
2. then you use the command: ifconfig ip down; make the network card of
master and standby down,
Observation
master can detect connect abnormal, but the standby can't detect connect
abnormal and show a connected channel long time.

Note - Earlier I had sent this on Hackers list also, I just wanted to know
that is it the behavior as defined by PostgreSQL or is it a bug or a new
feature in itself.

In case it is not clear, I will raise a bug.

With Regards,
Amit Kapila