Minor improvement to the resource manager.

This change affects cases where a sound is loaded while the same sound
is still in the process of being decoded. It makes it so the ASYNC flag
will only wait for the underlying data buffer to be initialized,
whereas the lack of ASYNC flag will result in it waiting for the entire
sound to be fully decoded.

research/miniaudio_engine.h

@@ -6743,8 +6743,17 @@ static ma_result ma_resource_manager_data_buffer_init_nolock(ma_resource_manager
             return result;  /* Should never happen. Failed to increment the reference count. */
         }
 
-        /* The existing node may be in the middle of loading. We need to wait for the node to finish loading before going any further. */
+        /*
+        The existing node may be in the middle of loading. We need to wait for the node to finish
+        loading before going any further or else we won't be able to initialize the connector. The
+        alternative to this could be to initialize the connector via the job queue when the data
+        source is being loaded asynchronously.
+        */
+        if (ma_resource_manager_data_buffer_node_result(pDataBuffer->pNode) == MA_BUSY) {
             if (ma_resource_manager_is_threading_enabled(pResourceManager)) {
+                if (async) {
+                    /* Loading asynchronously. */
+
                     /* TODO: This needs to be improved so that when loading asynchronously we post a message to the job queue instead of just waiting. */
                     if (pDataBuffer->pNode->data.type == ma_resource_manager_data_buffer_encoding_decoded) {
                         /* For the decoded case we need only wait for the data supplier to be initialized. */
@@ -6756,6 +6765,12 @@ static ma_result ma_resource_manager_data_buffer_init_nolock(ma_resource_manager
                             ma_yield();
                         }
                     }
+                } else {
+                    /* Loading synchronously. Wait for the initial sound to be fully decoded. */
+                    while (ma_resource_manager_data_buffer_node_result(pDataBuffer->pNode) == MA_BUSY) {
+                        ma_yield();
+                    }
+                }
             } else {
                 /* Threading is not enabled. We need to spin and call ma_resource_manager_process_next_job(). */
                 while (ma_resource_manager_data_buffer_node_result(pDataBuffer->pNode) == MA_BUSY) {
@@ -6765,6 +6780,7 @@ static ma_result ma_resource_manager_data_buffer_init_nolock(ma_resource_manager
                     }
                 }
             }
+        }
 
         result = ma_resource_manager_data_buffer_init_connector(pDataBuffer, NULL);
         if (result != MA_SUCCESS) {
@@ -12028,7 +12044,7 @@ MA_API ma_result ma_sound_init_copy(ma_engine* pEngine, const ma_sound* pExistin
 
     result = ma_resource_manager_data_source_init_copy(pEngine->pResourceManager, pExistingSound->pResourceManagerDataSource, pSound->pResourceManagerDataSource);
     if (result != MA_SUCCESS) {
-        ma_free(pSound, &pEngine->allocationCallbacks);
+        ma_free(pSound->pResourceManagerDataSource, &pEngine->allocationCallbacks);
         return result;
     }