log

type Backend interface {
	// Name returns the name of this backend.
	Name() string
	// Log emits log messages with the given severity, source, and Printf-like arguments.
	Log(Level, string, string, ...interface{})
	// Block emits a multi-line log messages, with an additional line prefix.
	Block(Level, string, string, string, ...interface{})
	// Flush flushes and stops initial buffering synchronously
	Flush()
	// Sync waits for all messages to get emitted.
	Sync()
	// Stop stops the backend instance.
	Stop()
	// SetSourceAlignment sets the maximum prefix length for optional alignment.
	SetSourceAlignment(int)
}

type BackendFn func() Backend

type Delayed interface {
	String() string
}

type Level int

type Logger interface {
	// Debug formats and emits a debug message.
	Debug(format string, args ...interface{})
	// Info formats and emits an informational message.
	Info(format string, args ...interface{})
	// Warn formats and emits a warning message.
	Warn(format string, args ...interface{})
	// Error formats and emits an error message.
	Error(format string, args ...interface{})
	// Panic formats and emits an error message then panics with the same.
	Panic(format string, args ...interface{})
	// Fatal formats and emits an error message and os.Exit()'s with status 1.
	Fatal(format string, args ...interface{})

	// DebugBlock formats and emits a multiline debug message.
	DebugBlock(prefix string, format string, args ...interface{})
	// InfoBlock formats and emits a multiline information message.
	InfoBlock(prefix string, format string, args ...interface{})
	// WarnBlock formats and emits a multiline warning message.
	WarnBlock(prefix string, format string, args ...interface{})
	// ErrorBlock formats and emits a multiline error message.
	ErrorBlock(prefix string, format string, args ...interface{})

	// EnableDebug enables debug messages for this Logger.
	EnableDebug(bool) bool
	// DebugEnabled checks if debug messages are enabled for this Logger.
	DebugEnabled() bool

	// Source returns the source name of this Logger.
	Source() string
}

type Rate struct {
	// rate limit
	Limit goxrate.Limit
	// allowed bursts
	Burst int
	// optional message window size
	Window int
}