Count first decode token in first_iter_counts

Signed-off-by: Samuel Monson <[email protected]>

Author: sjmonson

src/guidellm/benchmark/benchmark.py

@@ -817,7 +817,7 @@ def from_stats(
                     ],
                     iter_counts=[req.output_tokens for req in total_with_output_first],
                     first_iter_counts=[
-                        req.prompt_tokens for req in total_with_output_first
+                        req.prompt_tokens + 1 for req in total_with_output_first
                     ],
                 ),
             ),