Experimental, subject to change.
Returns a (fn clean [signal]) that:
  - Takes a Telemere  signal (map).
  - Returns a minimal signal (map) ready for printing, etc.

Signals are optimized for cheap creation and easy handling, so tend to be
verbose and may contain things like nil values and duplicated content.

This util efficiently cleans signals of such noise, helping reduce
storage/transmission size, and making key info easier to see.

Options:
  `:incl-nils?` - Include signal's keys with nil values? (default false)
  `:incl-kvs?`  - Include signal's app-level root kvs?   (default false)
  `:incl-keys`  - Subset of signal keys to retain from those otherwise
                  excluded by default: #{:location :kvs :file :host :thread}

Experimental, subject to change.
Returns true iff given signal has an `:error` value, or a `:kind` or `:level`
that indicates that it's an error.

Experimental, subject to change.
Opens the specified file and returns a stateful fn of 2 arities:
  [content] => Writes given content to file, or noops if closed.
  []        => Closes the writer.

Useful for basic handlers that write to a file, etc.

Notes:
  - Automatically creates file and parent dirs as necessary.
  - Writer should be manually closed after use (with zero-arity call).
  - Flushes after every write.
  - Thread safe, locks on single file stream.

Experimental, subject to change.
Returns a (fn format [error]) that:
  - Takes a platform error (`Throwable` or `js/Error`).
  - Returns a human-readable error string.

`:foo.bar/baz` -> "::baz", etc.

Experimental, subject to change without notice.

Returns a (fn format [instant]) that:
  - Takes a platform instant (`java.time.Instant` or `js/Date`).
  - Returns a formatted human-readable instant string.

Options:
  `:formatter`
    Clj:  `java.time.format.DateTimeFormatter`
    Cljs: `goog.i18n.DateTimeFormat`

    Defaults to `ISO8601` formatter (`YYYY-MM-DDTHH:mm:ss.sssZ`),
    e.g.: "2011-12-03T10:15:130Z".

  `:zone` (Clj only) `java.time.ZoneOffset` (defaults to UTC).
   Note that zone may be ignored by some `DateTimeFormatter`s,
   including the default (`DateTimeFormatter/ISO_INSTANT`)!

`:info` -> "INFO",
`5` -> "LEVEL:5", etc.

Returns "<ns/file>(<line>,<column>)", etc.

Experimental, subject to change.
Returns a (fn format [nanosecs]) that:
  - Takes a long nanoseconds (e.g. runtime).
  - Returns a human-readable string like:
    "1.00m", "4.20s", "340ms", "822μs", etc.

Experimental, subject to change.
Returns a (fn format [signal]) that:
  - Takes a Telemere signal (map).
  - Returns a human-readable signal string.

Options:
  `:incl-newline?` - Include terminating system newline? (default true)
  `:preamble-fn`   - (fn [signal]) => signal preamble string, see [1]
  `:content-fn`    - (fn [signal]) => signal content  string, see [2]

[1] `taoensso.telemere.utils/signal-preamble-fn`, etc.
[2] `taoensso.telemere.utils/signal-content-fn`,  etc.

See also `pr-signal-fn` for an alternative to `format-signal-fn`
that produces machine-readable output (edn, JSON, etc.).

Experimental, subject to change.
Returns a (fn hex-uid [root?]) that returns a random hex-style uid string like:
  "05039666eb9dc3206475f44ab9f3d843" - 128 bit (32 char)     root         uid
  "721fcef639a51513"                 - 64  bit (16 char) non-root (child) uid

Returns ?{:keys [ip name]} with string vals or `fallback-val` (default nil).
Arities 0 and 3 are   cached, prefer these!
Arities 1 and 2 are uncached and intended for advanced users only.

Returns local host IP string or `fallback-val` (default nil).
Arities 0 and 3 are   cached, prefer these!
Arities 1 and 2 are uncached and intended for advanced users only.

Returns local hostname string or `fallback-val` (default nil).
Arities 0 and 3 are   cached, prefer these!
Arities 1 and 2 are uncached and intended for advanced users only.

Experimental, subject to change.
Returns a (fn nano-uid [root?]) that returns a random nano-style uid string like:
  "r76-B8LoIPs5lBG1_Uhdy" - 126 bit (21 char)     root         uid
  "tMEYoZH0K-"            - 60  bit (10 char) non-root (child) uid

Single system newline

Prints given arg to an edn string readable with `read-edn`.

Experimental, subject to change.
Returns a (fn pr [signal]) that:
  - Takes a Telemere signal (map).
  - Returns a machine-readable signal string.

Options:
  `:pr-fn`         - ∈ #{<unary-fn> :edn (default) :json (Cljs only)}
  `:clean-fn`      - (fn [signal]) => clean signal map, see [1]
  `:incl-newline?` - Include terminating system newline? (default true)

Examples:

  ;; To print as edn:
  (pr-signal-fn {:pr-fn :edn})

  ;; To print as JSON:
  ;; Ref.  <https://github.com/metosin/jsonista> (or any alt JSON lib)
  #?(:clj (require '[jsonista.core :as jsonista]))
  (pr-signal-fn
    {:pr-fn
      #?(:cljs :json ; Use js/JSON.stringify
         :clj  jsonista/write-value-as-string)})

[1] `taoensso.telemere.utils/clean-signal-fn`, etc.

See also `format-signal-fn` for an alternative to `pr-signal-fn`
that produces human-readable output.

Experimental, subject to change.
Returns a (fn content [signal]) that:
  - Takes a Telemere signal (map).
  - Returns a human-readable signal content ?string (incl. data, ctx, etc.).

Options:
  `:raw-error?`      - Retain unformatted error? (default false)
  `:incl-keys`       - Subset of signal keys to retain from those
                       otherwise excluded by default: #{:kvs :host :thread}
  `:format-nsecs-fn` - (fn [nanosecs]) => string.
  `:format-error-fn` - (fn [error])    => string.

Experimental, subject to change.
Returns a (fn preamble [signal]) that:
  - Takes a Telemere signal (map).
  - Returns a signal preamble ?string like:
    "2024-03-26T11:14:51.806Z INFO EVENT Hostname taoensso.telemere(2,21) ::ev-id msg"

Options:
  `:format-inst-fn` - (fn format [instant]) => string.
  `:format-id-fn`   - (fn format [ns id])   => string.
  `:format-msg-fn`  - (fn format [msg])     => string.

Experimental, subject to change.
Connects to specified TCP socket and returns a stateful fn of 2 arities:
  [content] => Writes given content to socket, or noops if closed.
  []        => Closes the writer.

Useful for basic handlers that write to a TCP socket, etc.

Options:
  `:ssl?`                  - Use SSL/TLS?
  `:connect-timeout-msecs` - Connection timeout (default 3000 msecs)
  `:socket-fn`             - (fn [host port timeout]) => `java.net.Socket`
  `:ssl-socket-fn`         - (fn [socket host port])  => `java.net.Socket`

Notes:
  - Writer should be manually closed after use (with zero-arity call).
  - Flushes after every write.
  - Will retry failed writes once, then drop.
  - Thread safe, locks on single socket stream.
  - Advanced users may want a custom implementation using a connection
    pool and/or more sophisticated retry semantics, etc.

Returns long id of current `Thread`.

Returns {:keys [group name id]} for current `Thread`.

Returns string name of current `Thread`.

For Clj: returns a random `java.util.UUID`.
For Cljs: returns a random UUID string.

Uses strong randomness when possible.
See also `uuid-str`, `nanoid`, `rand-id-fn`.

Returns a random UUID string of given length (max 36).
Uses strong randomness when possible. See also `uuid`, `nanoid`, `rand-id-fn`.