Feature request

Feature description

For most rcl objects, the following code works:

rcl_<type>_t foo = rcl_get_zero_initialized_<type>();
assert(RCL_RET_OK == rcl_<type>_fini(&foo));

That's not the case for <type> = context, in that case it's returning RCL_RET_INVALID_ARGUMENT,

e.g.:

• rcl_publisher_fini.
• rcl_subscription_fini.
• rcl_context_fini.

I ran into this while working in rcljava.
Though this might be considered a bug in rcljava code, it's strange that we follow different semantics in constructor/destructor functions of different objects in the same package.

I think that it would also be great to have a clear style guide on how to name constructor/destructor in C code.