Configuration for Stasis threadpool

The appropriate settings for the Stasis threadpool is very system
specific, depending upon both workload and system configuration.

This patch adds a stasis.conf file which can be used to configure the
key attributes of the threadpool for the Stasis message bus.

(closes issue ASTERISK-21280)
Review: https://reviewboard.asterisk.org/r/2651/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@393542 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/stasis.h

@@ -809,15 +809,19 @@ void stasis_log_bad_type_access(const char *name);
 /*! @{ */
 
 /*!
- * \brief Initialize the Stasis subsystem
+ * \brief Initialize the Stasis subsystem.
  * \return 0 on success.
  * \return Non-zero on error.
  * \since 12
  */
 int stasis_init(void);
 
+/*! @} */
+
+/*! @{ */
+
 /*!
- * \private
+ * \internal
  * \brief called by stasis_init() for cache initialization.
  * \return 0 on success.
  * \return Non-zero on error.
@@ -825,6 +829,25 @@ int stasis_init(void);
  */
 int stasis_cache_init(void);
 
+/*!
+ * \internal
+ * \brief called by stasis_init for config initialization.
+ * \return 0 on success.
+ * \return Non-zero on error.
+ * \since 12
+ */
+int stasis_config_init(void);
+
+struct ast_threadpool_options;
+
+/*!
+ * \internal
+ * \brief Retrieves the Stasis threadpool configuration.
+ * \param[out] threadpool_options Filled with Stasis threadpool options.
+ */
+void stasis_config_get_threadpool_options(
+	struct ast_threadpool_options *threadpool_options);
+
 /*! @} */
 
 /*!