Collector builder functions are only used internally in the `collector`
package, and shouldn't needlessly be exposed as part of the package API
to downstream clients.
Signed-off-by: Ben Reedy <breed808@breed808.com>
Behaviour of init functions has been centralised in `collector/init.go`,
and can be called during exporter startup. This allows the exporter to
control the timing of collector initialisation, rather than relying on
the import & `init()` method.
This should reduce unexpected behaviour arising from the use of
`init()`, such as #551.
Signed-off-by: Ben Reedy <breed808@breed808.com>
See,
```
windows_memory_demand_zero_faults_total non-counter metrics should not have "_total" suffix
windows_memory_cache_faults_total non-counter metrics should not have "_total" suffix
windows_memory_page_faults_total non-counter metrics should not have "_total" suffix
windows_memory_pool_nonpaged_allocs_total non-counter metrics should not have "_total" suffix
windows_memory_pool_nonpaged_bytes_total non-counter metrics should not have "_total" suffix
windows_memory_pool_paged_allocs_total non-counter metrics should not have "_total" suffix
windows_memory_swap_page_operations_total non-counter metrics should not have "_total" suffix
windows_memory_swap_page_reads_total non-counter metrics should not have "_total" suffix
windows_memory_swap_page_writes_total non-counter metrics should not have "_total" suffix
windows_memory_swap_pages_read_total non-counter metrics should not have "_total" suffix
windows_memory_swap_pages_written_total non-counter metrics should not have "_total" suffix
windows_memory_transition_faults_total non-counter metrics should not have "_total" suffix
windows_memory_transition_pages_repurposed_total non-counter metrics should not have "_total" suffix
windows_memory_write_copies_total non-counter metrics should not have "_total" suffix
```
Only `windows_memory_pool_nonpaged_bytes` is a gauge, all the other
metrics were counters.
Also added some missing documentation.
Signed-off-by: Mario Trangoni <mjtrangoni@gmail.com>
