Decide whether to Chunked after body encoding.

[siwee]

Motivation:

Decide whether to Chunked after body encoding. Netty will automatically calculate the Content-length. When the Content-length is greater than 8k, it will not set the Content-length header value, so we can decide whether to Chunk or not based on it.
If it is up to the developer to set the content-length value, it is likely to cause an error. In addition, when sending the application/x-www-form-urlencoded form, it will cause chunked=true, which is not necessary, usually the body is very small.

Conformance:

Your commits should be signed and you should have signed the Eclipse Contributor Agreement as explained in https://github.com/eclipse/vert.x/blob/master/CONTRIBUTING.md
Please also make sure you adhere to the code style guidelines: https://github.com/vert-x3/wiki/wiki/Vert.x-code-style-guidelines

[vietj]

it is not clear what this PR is doing, can you elaborate ?

[siwee]

@vietj Hi.

I'm so sorry, English is not my native language. 😂

I think these may be problematic.

When we send the application/x-www-form-urlencoded form, no matter the size of the body, it will be sent in Chunked mode. Is this necessary? Most of the body is very small, I think this increases the processing complexity.

[siwee]

Currently, the Content-length is verified through the HttpRequest Header, which may be incorrect, and we do not know the specific value through it.

[siwee]

I tested this PR and it works well.

[vietj]

You need to add a test, then I'll have a look, perhaps it can be handled in vertx-core instead