Add threading primitives.

PiperOrigin-RevId: 562649644
Change-Id: I9c35b270e4b3b50cc7eb5a152f24d71def8e2fcd

include/mujoco/mujoco.h

@@ -36,6 +36,7 @@ extern "C" {
 #include <mujoco/mjmacro.h>
 #include <mujoco/mjplugin.h>
 #include <mujoco/mjrender.h>
+#include <mujoco/mjthread.h>
 #include <mujoco/mjtnum.h>
 #include <mujoco/mjui.h>
 #include <mujoco/mjvisualize.h>
@@ -1304,6 +1305,21 @@ MJAPI const mjpResourceProvider* mjp_getResourceProvider(const char* resource_na
 // If invalid slot number, return NULL.
 MJAPI const mjpResourceProvider* mjp_getResourceProviderAtSlot(int slot);
 
+//---------------------- Thread -------------------------------------------------------------------
+
+// Creates a thread pool with the specified number of threads running.
+MJAPI mjThreadPool* mju_threadPoolCreate(size_t number_of_threads);
+
+// Enqueues a task in a thread pool.
+MJAPI void mju_threadPoolEnqueue(
+    mjThreadPool* thread_pool, mjTask* task, void*(start_routine)(void*),
+    void* args);
+
+// Waits for a task to complete.
+MJAPI void mju_taskJoin(mjTask* task);
+
+// Destroys a thread pool.
+MJAPI void mju_threadPoolDestroy(mjThreadPool* thread_pool);
 
 #if defined(__cplusplus)
 }