feat: introduces an option for a custom body size in websocket.Dial function

[IgorSilvestre]

Why

Feature asked by this issue:

• Any chance of bubbling up HTTP errors? #528

What

• Introduce DialOptions.MaxErrorResponseBodyBytes so callers can opt into more (or zero) error-body
  bytes when the handshake fails, enabling better branching on status/body while keeping the default
  1024-byte limit.
• Preserve existing success-path behavior and safety: response bodies stay nil on success; 3s timeout
  still guards error-body reads; disabled option closes without reading.

Key Changes

• dial.go: use new option to bound error-body capture; skip capture if set < 0; guard nil bodies;
  still close original body with 3s fail-safe.
• dial_test.go: new/updated tests covering default cap, custom cap, disabled capture (ensures close),
  status code presence, and nil-body safety.

Testing

I did some testing with a dummy server responding a fixed status 400 and a 1mb body:

[mafredri]

Closing this as it does not address #528, which does not request an increase in body size.

[IgorSilvestre]

Closing this as it does not address #528, which does not request an increase in body size.

Fair, I assumed in

and ideally the body too. Is there any chance of modifying Dial to return this information"

that he would want to return more of the body, seeing its already returning 1024b.

[mafredri]

@IgorSilvestre no worries. Thanks for attempting a fix. We are very conservative with expanding API surface in this project and there would have to be a real and obvious need if we were to add something.

[IgorSilvestre]

@IgorSilvestre no worries. Thanks for attempting a fix. We are very conservative with expanding API surface in this project and there would have to be a real and obvious need if we were to add something.

On reading other issues I saw that minimizing the API is something important for you, no problem.

I really like this project, if ever need a hand with something just ask.