simplified rateLimiter

resists better to changing in/out conditions
limits risks of "catching up"

tests/rateLimiter.py

@@ -19,30 +19,22 @@ import time
 
 MB = 1024 * 1024
 rate = float(sys.argv[1]) * MB
-rate *= 1.4   # compensation for excluding i/o time (experimentally determined)
 start = time.time()
 total_read = 0
 
-sys.stderr.close()  # remove error message, for Ctrl+C
+# sys.stderr.close()  # remove error message, for Ctrl+C
 
 try:
   buf = " "
   while len(buf):
     now = time.time()
-    to_read = max(int(rate * (now - start) - total_read), 1)
+    to_read = max(int(rate * (now - start)), 1)
     max_buf_size = 1 * MB
     to_read = min(to_read, max_buf_size)
+    start = now
 
-    read_start = time.time()
     buf = sys.stdin.buffer.read(to_read)
-
-    write_start = read_end = time.time()
     sys.stdout.buffer.write(buf)
-    write_end = time.time()
-
-    wait_time = max(read_end - read_start, write_end - write_start)
-    start += wait_time   # exclude delay of the slowest
-    total_read += len(buf)
 
 except (KeyboardInterrupt, BrokenPipeError) as e:
     pass