Emits a logs entry with a message, and data attached to

Log.info &.emit("Program started")                         # No data, same as Log.info { "Program started" }
Log.info &.emit("User logged in", user_id: 42)             # With entry data
Log.info &.emit(action: "Logged in", user_id: 42)          # Empty string message, only data
Log.error exception: ex, &.emit("Oops", account: {id: 42}) # With data and exception