added documentation for executor_threads

Author: 111andre111

docs/index.asciidoc

@@ -93,6 +93,7 @@ This plugin supports the following configuration options plus the <<plugins-{typ
 | <<plugins-{type}s-{plugin}-add_hostname>> |<<boolean,boolean>>|No
 | <<plugins-{type}s-{plugin}-cipher_suites>> |<<array,array>>|No
 | <<plugins-{type}s-{plugin}-client_inactivity_timeout>> |<<number,number>>|No
+| <<plugins-{type}s-{plugin}-executor_threads>> |<<number,number>>|No
 | <<plugins-{type}s-{plugin}-host>> |<<string,string>>|No
 | <<plugins-{type}s-{plugin}-include_codec_tag>> |<<boolean,boolean>>|No
 | <<plugins-{type}s-{plugin}-port>> |<<number,number>>|Yes
@@ -140,6 +141,14 @@ The list of ciphers suite to use, listed by priorities.
 
 Close Idle clients after X seconds of inactivity.
 
+[id="plugins-{type}s-{plugin}-executor_threads"]
+===== `executor_threads`
+
+  * Value type is <<number,number>>
+  * Default value is 1 executor thread per CPU core
+
+The number of parallel executor threads.
+
 [id="plugins-{type}s-{plugin}-host"]
 ===== `host`