Create Go maps in inlinedExtraData lazily

map.go

@@ -2502,7 +2502,7 @@ func DecodeInlinedCompactMapStorable(
 	copy(hkeys, extraData.hkeys)
 
 	// Decode values
-	size := uint32(hkeyElementsPrefixSize)
+	elementsSize := uint32(hkeyElementsPrefixSize)
 	elems := make([]element, elemCount)
 	for i := 0; i < int(elemCount); i++ {
 		value, err := decodeStorable(dec, slabID, inlinedExtraData)
@@ -2517,15 +2517,15 @@ func DecodeInlinedCompactMapStorable(
 		elem := &singleElement{key, value, elemSize}
 
 		elems[i] = elem
-		size += digestSize + elem.Size()
+		elementsSize += digestSize + elem.Size()
 	}
 
 	// Create hkeyElements
 	elements := &hkeyElements{
 		hkeys: hkeys,
 		elems: elems,
 		level: 0,
-		size:  size,
+		size:  elementsSize,
 	}
 
 	header := MapSlabHeader{

typeinfo.go

@@ -206,10 +206,7 @@ type inlinedExtraData struct {
 }
 
 func newInlinedExtraData() *inlinedExtraData {
-	return &inlinedExtraData{
-		compactMapTypes: make(map[string]compactMapTypeInfo),
-		arrayTypes:      make(map[string]int),
-	}
+	return &inlinedExtraData{}
 }
 
 // Encode encodes inlined extra data as CBOR array.
@@ -311,6 +308,10 @@ func newInlinedExtraDataFromData(
 // Array extra data is deduplicated by array type info ID because array
 // extra data only contains type info.
 func (ied *inlinedExtraData) addArrayExtraData(data *ArrayExtraData) int {
+	if ied.arrayTypes == nil {
+		ied.arrayTypes = make(map[string]int)
+	}
+
 	id := data.TypeInfo.ID()
 	index, exist := ied.arrayTypes[id]
 	if exist {
@@ -339,6 +340,10 @@ func (ied *inlinedExtraData) addCompactMapExtraData(
 	keys []ComparableStorable,
 ) (int, []ComparableStorable) {
 
+	if ied.compactMapTypes == nil {
+		ied.compactMapTypes = make(map[string]compactMapTypeInfo)
+	}
+
 	id := makeCompactMapTypeID(data.TypeInfo, keys)
 	info, exist := ied.compactMapTypes[id]
 	if exist {