Response header size dropped from "total data received" summary due to operator precedence bug

Description

RunSummary's request tracker computes run.transfers.responseTotal (shown in the CLI reporter as total data received: ... (approx)) using:

https://github.com/postmanlabs/newman/blob/develop/lib/run/summary.js#L315

size && (summary.run.transfers.responseTotal += (size.body || 0 + size.headers || 0));

Because + binds tighter than || in JavaScript, this parses as:

size.body || (0 + size.headers) || 0

not the intended:

(size.body || 0) + (size.headers || 0)

Impact

Whenever a response has a non-zero body size (i.e. almost always), size.headers is silently dropped from the running total — only size.body is counted. The "total data received" figure printed at the end of every collection run is therefore consistently undercounted by the size of all response headers across the run.

Repro

const size = { body: 270, headers: 793 };

console.log(size.body || 0 + size.headers || 0);        // 270  (headers silently dropped)
console.log((size.body || 0) + (size.headers || 0));    // 1063 (correct)

This is also confirmed by the existing test suite's own TODO in test/unit/run-summary.test.js:

// @todo add test for computation of timings, transfer sizes and average response time

i.e. this computation currently has zero test coverage, which is how the bug went unnoticed.

Fix

Add explicit parens so + happens before ||:

size && (summary.run.transfers.responseTotal += ((size.body || 0) + (size.headers || 0)));

PR: https://github.com/Adityaj0/newman/pull/2