teardown on never connected RelpConnection throws npe

[kortemik]

Describe the bug

Cannot invoke "java.nio.channels.SocketChannel.close()" because "this.socketChannel" is null> java.lang.NullPointerException: Cannot invoke "java.nio.channels.SocketChannel.close()" because "this.socketChannel" is null
        at com.teragrep.rlp_01.RelpClientPlainSocket.close(RelpClientPlainSocket.java:150)
        at com.teragrep.rlp_01.RelpConnection.tearDown(RelpConnection.java:169)

when connection has never been connected

Expected behavior
shouldn't throw, should just be no-op because there is nothing to teardown

How to reproduce
create new RelpConnection and immediately call teardown() on it.

Screenshots

Software version
4.0.1

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Additional context