Add heap usage for PK in benchmark
diff --git a/include/polarssl/memory_buffer_alloc.h b/include/polarssl/memory_buffer_alloc.h
index ab36b41..3bba1c1 100644
--- a/include/polarssl/memory_buffer_alloc.h
+++ b/include/polarssl/memory_buffer_alloc.h
@@ -97,6 +97,27 @@
  *          trace if POLARSSL_MEMORY_BACKTRACE is defined.
  */
 void memory_buffer_alloc_status( void );
+
+/**
+ * \brief   Get the peak heap usage so far
+ *
+ * \param max_used      Peak number of bytes reauested by the application
+ * \param max_blocks    Peak number of blocks reauested by the application
+ */
+void memory_buffer_alloc_max_get( size_t *max_used, size_t *max_blocks );
+
+/**
+ * \brief   Reset peak statistics
+ */
+void memory_buffer_alloc_max_reset( void );
+
+/**
+ * \brief   Get the current heap usage
+ *
+ * \param cur_used      Number of bytes reauested by the application
+ * \param cur_blocks    Number of blocks reauested by the application
+ */
+void memory_buffer_alloc_cur_get( size_t *cur_used, size_t *cur_blocks );
 #endif /* POLARSSL_MEMORY_DEBUG */
 
 /**