log4stach elastic search appender memory leak about log4stash HOT 4 OPEN

<?xml version="1.0" encoding="utf-8"?>
<log4net>
	<root>
		<level value="ALL" />
		<appender-ref ref="elasticsearch" />
	</root>
	<appender name="elasticsearch" type="log4stash.ElasticSearchAppender, log4stash">
		<Server><!-- redacted --></Server>
		<Port>443</Port>
		<AllowSelfSignedServerCert>False</AllowSelfSignedServerCert>
		<Ssl>True</Ssl>
		<AuthenticationMethod>
			<Basic>
				<Username><!-- redacted --></Username>
				<Password><!-- redacted --></Password>
			</Basic>
		</AuthenticationMethod>

		<IndexName>%{environment}-%{application}-%{log.level}-%{+yyyy-MM-dd}</IndexName>
		<IndexType>_doc</IndexType>
		<IndexAsync>False</IndexAsync>

		<BulkSize>256</BulkSize><!-- we're getting lots of payload too large messages -->
		<BulkIdleTimeout>5000</BulkIdleTimeout>
		<DropEventsOverBulkLimit>False</DropEventsOverBulkLimit>
		<ElasticSearchTimeout>90000</ElasticSearchTimeout><!-- we're getting connection rejected a lot from the server; I'd like to increase BulkSize, but with the payload too large messages, I don't think I can right now -->

		<SerializeObjects>True</SerializeObjects>

		<FixedFields>Partial</FixedFields>

		<ElasticFilters>
			<Remove>
				<Key>log4net:HostName</Key>
			</Remove>
			<Remove>
				<Key>log4net:Identity</Key>
			</Remove>

			<Rename>
				<Key>AppDomain</Key>
				<RenameTo>application</RenameTo>
			</Rename>
			<Rename>
				<Key>HostName</Key>
				<RenameTo>host.name</RenameTo>
			</Rename>
			<Rename>
				<Key>Level</Key>
				<RenameTo>log.level</RenameTo>
			</Rename>
			<Rename>
				<Key>log4net:UserName</Key>
				<RenameTo>UserName</RenameTo>
			</Rename>
			<Rename>
				<Key>LoggerName</Key>
				<RenameTo>log.logger</RenameTo>
			</Rename>
			<Rename>
				<Key>Message</Key>
				<RenameTo>message.text</RenameTo>
			</Rename>
			<Rename>
				<Key>ThreadName</Key>
				<RenameTo>thread.name</RenameTo>
			</Rename>
			<Rename>
				<Key>UserName</Key>
				<RenameTo>server.user.name</RenameTo>
			</Rename>
		</ElasticFilters>
	</appender>
</log4net>