Prior to this commit, NettyDataBuffer had a optimization in
write(ByteBuf...), where it used a CompositeByteBuf to hold the original
and the parameter buffer.
Unfortunately, this procedure has nasty consequences when splicing
buffers (see https://stackoverflow.com/a/48111196/839733).

As of this commit, NettyDataBuffer stopped using CompositeByteBuf, and
 simply does ByteBuf.write().

Issue: SPR-16351

Issue: SPR-16290

Issue: SPR-16245

Includes default implementations of getSqlType and getTypeName.

Issue: SPR-16361

Includes efficient separator determination.

Issue: SPR-16340

Issue: https://jira.spring.io/browse/SPR-16235

* pr/1640:
  Fix source code in doc

Closes gh-1640

Optimize same origin check when the request is an instance of
ServletServerHttpRequest and when there is no forwarded headers.

This commit also optimizes the getPort methods and ForwardedHeaderFilter
forwarded headers checks.

Issue: SPR-16262

This commit refines forwarded protocol support in order to support
proxies that only set "X-Forwarded-Proto" header and not
"X-Forwarded-Port" by performing a reset of the port in such case.

"Forwarded" header support has been updated accordingly since it
also supports similar use case, as described in SPR-15504.

Issue: SPR-16262

Issue: SPR-16214

Issue: SPR-16324

Issue: SPR-16322

Issue: SPR-16266

Issue: SPR-16356

Issue: SPR-16315

Issue: SPR-16353

Issue: SPR-16352

Issue: SPR-13481

Issue SPR-16248

Issue: SPR-16255

Issue: SPR-16347

Issue: SPR-16343

Issue: SPR-16250

Issue: SPR-16278

Issue: SPR-16284

Issue: SPR-16281

Issue: SPR-16334

Issue: SPR-16298

The issue was introduced very recently with commit #7035ee but never
released.

Issue: SPR-16350

Issue: SPR-16260

Cross-reference sections on HttpMessageReader/Writer and
HttpMessageConverter and improve the content.

Issue: SPR-16260