Make LazyMultiError only constructable via function

common/errors/multierror.go

Index: common/errors/multierror.go
diff --git a/common/errors/multierror.go b/common/errors/multierror.go
index df812b643251d497f1f01b0a17014acb78b28687..1a051c4399b0e5dd68fb5993eb2e3ea3e8c05571 100644
--- a/common/errors/multierror.go
+++ b/common/errors/multierror.go
@@ -7,7 +7,6 @@ package errors
 import (
 	"fmt"
 	"reflect"
-	"sync"
 )
 
 var (
@@ -73,57 +72,6 @@ func MultiErrorFromErrors(ch <-chan error) error {
 	return ret
 }
 
-// LazyMultiError is a lazily-constructed MultiError. You specify the target
-// MultiError size up front (as Size), and then you call Assign for each error
-// encountered, and it's potential index. The MultiError will only be allocated
-// if one of the Assign'd errors is non-nil. Similarly, Get will retrieve either
-// the allocated MultiError, or nil if no error was encountered.
-type LazyMultiError struct {
-	sync.Mutex
-
-	Size int
-	me   MultiError
-}
-
-// Assign semantically assigns the error to the given index in the MultiError.
-// If the error is nil, no action is taken. Otherwise the MultiError is
-// allocated to its full size (if not already), and the error assigned into it.
-//
-// It returns true iff err != nil.
-func (e *LazyMultiError) Assign(i int, err error) bool {
-	if err == nil {
-		return false
-	}
-	e.Lock()
-	defer e.Unlock()
-	if e.me == nil {
-		e.me = make(MultiError, e.Size)
-	}
-	e.me[i] = err
-	return true
-}
-
-// GetOne returns the error at the given index, or nil, if no non-nil error
-// was Assign'd.
-func (e *LazyMultiError) GetOne(i int) error {
-	e.Lock()
-	defer e.Unlock()
-	if e.me == nil {
-		return nil
-	}
-	return e.me[i]
-}
-
-// Get returns the MultiError, or nil, if no non-nil error was Assign'd.
-func (e *LazyMultiError) Get() error {
-	e.Lock()
-	defer e.Unlock()
-	if e.me == nil {
-		return nil
-	}
-	return e.me
-}
-
 // Fix will convert a MultiError compatible type (e.g. []error) to this
 // version of MultiError.
 func Fix(err error) error {