There is a `hyper_clientconn_free` call on the happy path, but not one
on the error path. This commit adds one.

Fixes the second memory leak reported by Valgrind in #10803.

Fixes #10803
Closes #11729

Curl had two memory leaks in its usage of the hyper C API. I fixed these
in curl/curl#11729. While fixing these, as a
hyper newbie I found a lack of clarity in the docs about where the
responsibilities lie for allocating and deallocating things. I had to
repeatedly look at the `Box::into_raw`/`Box::from_raw` calls in the C
API code to properly understand things.

This commit extends the docs.
- For all functions that allocate things, make it clear which functions
  can be used to subsequently deallocate.
- For all functions that free things, make it clear if there are (or
  aren't) other functions that may have otherwise consumed the thing,
  thus removing the need for explicit freeing.
- Clarify some functions that consume things.

This is the documentation I wished was present when I was fixing the
leaks in curl.

Curl had two memory leaks in its usage of the hyper C API. I fixed these
in curl/curl#11729. While fixing these, as a
hyper newbie I found a lack of clarity in the docs about where the
responsibilities lie for allocating and deallocating things. I had to
repeatedly look at the `Box::into_raw`/`Box::from_raw` calls in the C
API code to properly understand things.

This commit extends the docs.
- For all functions that allocate things, make it clear which functions
  can be used to subsequently deallocate.
- For all functions that free things, make it clear if there are (or
  aren't) other functions that may have otherwise consumed the thing,
  thus removing the need for explicit freeing.
- Clarify some functions that consume things.

This is the documentation I wished was present when I was fixing the
leaks in curl.

Curl had two memory leaks in its usage of the hyper C API. I fixed these
in curl/curl#11729. While fixing these, as a
hyper newbie I found a lack of clarity in the docs about where the
responsibilities lie for allocating and deallocating things. I had to
repeatedly look at the `Box::into_raw`/`Box::from_raw` calls in the C
API code to properly understand things.

This commit extends the docs.
- For all functions that allocate things, make it clear which functions
  can be used to subsequently deallocate.
- For all functions that free things, make it clear if there are (or
  aren't) other functions that may have otherwise consumed the thing,
  thus removing the need for explicit freeing.
- Clarify some functions that consume things.

This is the documentation I wished was present when I was fixing the
leaks in curl.

Curl had two memory leaks in its usage of the hyper C API. I fixed these
in curl/curl#11729. While fixing these, as a
hyper newbie I found a lack of clarity in the docs about where the
responsibilities lie for allocating and deallocating things. I had to
repeatedly look at the `Box::into_raw`/`Box::from_raw` calls in the C
API code to properly understand things.

This commit extends the docs.
- For all functions that allocate things, make it clear which functions
  can be used to subsequently deallocate.
- For all functions that free things, make it clear if there are (or
  aren't) other functions that may have otherwise consumed the thing,
  thus removing the need for explicit freeing.
- Clarify some functions that consume things.

This is the documentation I wished was present when I was fixing the
leaks in curl.

Curl had two memory leaks in its usage of the hyper C API. I fixed these
in curl/curl#11729. While fixing these, as a
hyper newbie I found a lack of clarity in the docs about where the
responsibilities lie for allocating and deallocating things. I had to
repeatedly look at the `Box::into_raw`/`Box::from_raw` calls in the C
API code to properly understand things.

This commit extends the docs.
- For all functions that allocate things, make it clear which functions
  can be used to subsequently deallocate.
- For all functions that free things, make it clear if there are (or
  aren't) other functions that may have otherwise consumed the thing,
  thus removing the need for explicit freeing.
- Clarify some functions that consume things.

This is the documentation I wished was present when I was fixing the
leaks in curl.

A request created with `hyper_request_new` must be consumed by either
`hyper_clientconn_send` or `hyper_request_free`.

This is not terrifically clear from the hyper docs --
`hyper_request_free` is documented only with "Free an HTTP request if
not going to send it on a client" -- but a perusal of the hyper code
confirms it.

This commit adds a `hyper_request_free` to the `error:` path in
`Curl_http` so that the request is consumed when an error occurs after
the request is created but before it is sent.

Fixes the first memory leak reported by Valgrind in curl#10803.

Closes curl#11729

There is a `hyper_clientconn_free` call on the happy path, but not one
on the error path. This commit adds one.

Fixes the second memory leak reported by Valgrind in curl#10803.

Fixes curl#10803
Closes curl#11729

Curl had two memory leaks in its usage of the hyper C API. I fixed these
in curl/curl#11729. While fixing these, as a
hyper newbie I found a lack of clarity in the docs about where the
responsibilities lie for allocating and deallocating things. I had to
repeatedly look at the `Box::into_raw`/`Box::from_raw` calls in the C
API code to properly understand things.

This commit extends the docs.
- For all functions that allocate things, make it clear which functions
  can be used to subsequently deallocate.
- For all functions that free things, make it clear if there are (or
  aren't) other functions that may have otherwise consumed the thing,
  thus removing the need for explicit freeing.
- Clarify some functions that consume things.

This is the documentation I wished was present when I was fixing the
leaks in curl.

Curl had two memory leaks in its usage of the hyper C API. I fixed these
in curl/curl#11729. While fixing these, as a
hyper newbie I found a lack of clarity in the docs about where the
responsibilities lie for allocating and deallocating things. I had to
repeatedly look at the `Box::into_raw`/`Box::from_raw` calls in the C
API code to properly understand things.

This commit extends the docs.
- For all functions that allocate things, make it clear which functions
  can be used to subsequently deallocate.
- For all functions that free things, make it clear if there are (or
  aren't) other functions that may have otherwise consumed the thing,
  thus removing the need for explicit freeing.
- Clarify some functions that consume things.

This is the documentation I wished was present when I was fixing the
leaks in curl.

Signed-off-by: Sven Pfennig <s.pfennig@reply.de>