log/field.go
func Int(key string, val int) Field {
	return Field{
		key:        key,
		fieldType:  intType,
		numericVal: int64(val),
	}
}
func Int(key string, val int) Field {
	return Field{
		key:        key,
		fieldType:  intType,
		numericVal: int64(val),
	}
}
// Int adds an int-valued key:value pair to a Span.LogFields() record