This change adds 'SPDX-License-Identifier: BSD-2-Clause' [1] to
the source code files that originate in the libcoap project.
Note that not all files are tagged because they are pulled in
from other sources and thus may fall under a different license.
More information about these is contained in the LICENSE file.
[1] https://spdx.org/licenses/BSD-2-Clause.html
The original requesting PDU is now kept with the Observe request along with
its data and used whenever an additional response needs to be generated.
Abstracted information from the requesting PDU is no longer kept in
coap_subscription_t as it can be obtained from the kept PDU.
No longer any need to check for request PDU in request handlers as it is now
always provided.
coap_resource_notify_observers() now ignores the query parameter, as a
cache_key is now used for request matching.
Olaf Bergmann