fix(http2): send body for non-expectsPayload methods with content

[mcollina]

Fixes #5027

Summary

HTTP/2 crashes with AssertionError: buffer body must have content length when sending DELETE (or other non-expectsPayload methods) with a body.

Root Cause

In lib/dispatcher/client-h2.js, the writeH2 function unconditionally set contentLength = null for all methods that don't expect a payload (DELETE, GET, HEAD, etc.). However, when a body was provided, it still got passed to writeBodyH2, which then called writeBuffer with body and null contentLength. The writeBuffer function asserts contentLength === body.byteLength, which fails when contentLength is null.

Fix

Changed line 625 from:

if (!expectsPayload) {

to:

if (contentLength === 0 && !expectsPayload) {

This matches the H1 behavior and only omits the Content-Length header when the body is empty for methods that don't expect a payload. When a body is present, the Content-Length header is included and the body is sent correctly.

Testing

• All existing HTTP/2 tests pass (42 tests)
• All client and content-length tests pass (342 tests)
• Verified the fix resolves the reported issue with DELETE + body over HTTP/2

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.03%. Comparing base (6824eed) to head (b94f09b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5030      +/-   ##
==========================================
- Coverage   93.04%   93.03%   -0.02%     
==========================================
  Files         110      110              
  Lines       35793    35793              
==========================================
- Hits        33305    33301       -4     
- Misses       2488     2492       +4     

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[metcoder95]

regression test?