JIRA: https://jira.spring.io/browse/INT-4465
There is a one second delay before a socket close is propagated if there is an active
assembler. This is generally only a problem with deserializers that use EOF to signal
message end (such as the `ByteArrayElasticRawDeserializer`).
Attempt to insert an EOF marker into the buffer queue so that the `getNextBuffer()` will
exit immediately on `close()` if it is blocked awaiting a buffer.
**cherry-pick to 5.0.x, 4.3.x**
(cherry picked from commit d9186f1)
9dcb28bed8