INT-3575 TcpNetConnection: flush stream in send()

JIRA: https://jira.spring.io/browse/INT-3575
INT-3466: IMAP: Move `peek` Option to Properties

JIRA: https://jira.spring.io/browse/INT-3466

INT-3466 Add Docs
INT-3450 Support RFC 5424/6587 for SYSLOG

JIRA: https://jira.spring.io/browse/INT-3450

Use LinkedHashMap

- natural iteration order

INT-3450 Polishing - PR Comments

INT-3450: Polishing