This crate provides an asynchronous logging backend that can direct logs to
one or more outputs.
The core of this crate is the `RingLog` type, which is constructed using a
builder that is specific to your logging needs. After building the
`RingLog`, it can be registered as the global logger using the `start`
method. You will be left with a `Box` which should be
periodically flushed outside of any critical path. For example, in an admin
thread or dedicated logging thread.
For logging to a single file, the `LogBuilder` type can be used to construct
an `RingLog` which has low overhead, but directs log messages to a single
`Output`.
A `SamplingLogBuilder` can be used to construct an `RingLog` which will
filter the log messages using sampling before directing the log messages to
a single `Output`.
A `MultiLogBuilder` can be used to construct an `RingLog` which routes log
messages based on the `target` metadata of the log `Record`. If there is an
`RingLog` registered for that specific `target`, then the log message will
be routed to that instance of `RingLog`. Log messages that do not match any
specific target will be routed to the default `RingLog` that has been added
to the `MultiLogBuilder`. If there is no default, messages that do not match
any specific target will be simply dropped.
This combination of logging types allows us to compose a logging backend
which meets the application's needs. For example, you can use a local log
macro to set the target to some specific category and log those messages to
a file, while letting all other log messages pass to standard out. This
could allow splitting command/access/audit logs from the normal logging.