add pydarshan support for extra_info

Author: Shane Snyder

darshan-util/pydarshan/darshan/backend/api_def_c.py

@@ -205,6 +205,7 @@
     int64_t length;
     double start_time;
     double end_time;
+    char extra_info[64];
 } segment_info;
 
 /* counter names */

darshan-util/pydarshan/darshan/backend/cffi_backend.py

@@ -626,7 +626,8 @@ def log_get_dxt_record(log, mod_name, reads=True, writes=True, dtype='dict'):
             "offset": segments[i].offset,
             "length": segments[i].length,
             "start_time": segments[i].start_time,
-            "end_time": segments[i].end_time
+            "end_time": segments[i].end_time,
+            "extra_info": ffi.string(segments[i].extra_info).decode("utf-8")
         }
         rec['write_segments'].append(seg)
 
@@ -637,7 +638,8 @@ def log_get_dxt_record(log, mod_name, reads=True, writes=True, dtype='dict'):
             "offset": segments[i].offset,
             "length": segments[i].length,
             "start_time": segments[i].start_time,
-            "end_time": segments[i].end_time
+            "end_time": segments[i].end_time,
+            "extra_info": ffi.string(segments[i].extra_info).decode("utf-8")
         }
         rec['read_segments'].append(seg)