func NewSimpleString(m string) Composer {
	return &stringMessage{Message: m, skipMetadata: true}
}
NewSimpleString produces a string message that does not attach
process metadata.
package message
import "github.com/mongodb/grip/level"
type stringMessage struct {
	Message string `bson:"message" json:"message" yaml:"message"`
	Base    `bson:"metadata" json:"metadata" yaml:"metadata"`
	skipMetadata bool
}
func NewDefaultMessage(p level.Priority, message string) Composer {
	m := &stringMessage{Message: message}
	_ = m.SetPriority(p)
	return m
}
func NewString(m string) Composer {
	return &stringMessage{Message: m}
}