Blocking close()

[zzz]

MessageOutputStream?.close() and thus I2PSocketFull.close() is blocking. This is like SO_LINGER by default?

This is not standard socket behavior and isn't well-documented. Should it be changed and should we add setSoLinger() support? What would break if we changed it? Do we change flush() also? See comments in MessageOutputStream?.close(). If we don't change it, enhance the javadocs and website docs.