Configure a time limit (in milliseconds) for the maximum amount of a time
allowed when sending messages to a WebSocket session or writing to an
HTTP response when SockJS fallback option are in use.
In general WebSocket servers expect that messages to a single WebSocket
session are sent from a single thread at a time. This is automatically
guaranteed when using
@EnableWebSocketMessageBroker configuration.
If message sending is slow, or at least slower than rate of messages sending,
subsequent messages are buffered until either the
sendTimeLimitor the
sendBufferSizeLimit are reached at which point the session
state is cleared and an attempt is made to close the session.
NOTE that the session time limit is checked only
on attempts to send additional messages. So if only a single message is
sent and it hangs, the session will not time out until another message is
sent or the underlying physical socket times out. So this is not a
replacement for WebSocket server or HTTP connection timeout but is rather
intended to control the extent of buffering of unsent messages.
NOTE that closing the session may not succeed in
actually closing the physical socket and may also hang. This is true
especially when using blocking IO such as the BIO connector in Tomcat
that is used by default on Tomcat 7. Therefore it is recommended to ensure
the server is using non-blocking IO such as Tomcat's NIO connector that
is used by default on Tomcat 8. If you must use blocking IO consider
customizing OS-level TCP settings, for example
/proc/sys/net/ipv4/tcp_retries2 on Linux.
The default value is 10 seconds (i.e. 10 * 10000).