docs: document map read/write behaviour while ranging

Signed-off-by: m-murad <[email protected]>

map.go

@@ -71,6 +71,8 @@ func (m *Map) Delete(key interface{}) bool {
 
 // UnorderedRange will range over the map in an unordered sequence.
 // This is same as ranging over a map using the "for range" syntax.
+// Parameter func f should not call any method of the Map, eg Get, Put, Delete, UnorderedRange, OrderedRange etc
+// It will cause a deadlock
 func (m *Map) UnorderedRange(f func(key interface{}, value interface{})) {
 	m.mu.RLock()
 	for k, v := range m.mp {
@@ -83,6 +85,8 @@ func (m *Map) UnorderedRange(f func(key interface{}, value interface{})) {
 // This is way faster than UnorderedRange. For a map containing 10_000_000 items
 // UnorderedRange completes in ~1.7 seconds,
 // OrderedRange completes in ~98 milli seconds.
+// Parameter func f should not call any method of the Map, eg Get, Put, Delete, UnorderedRange, OrderedRange etc
+// It will cause a deadlock
 func (m *Map) OrderedRange(f func(key interface{}, value interface{})) {
 	m.mu.RLock()
 	cur := m.dll.Back()

readme.md

@@ -27,12 +27,14 @@ func main() {
 
     // UnorderedRange will iterate over the Map in a random sequence.
     // This is same as ranging over a map using the "for range" syntax.
+    // Parameter function should not call any methods associated with the map. 
     m.UnorderedRange(func(key interface{}, val interface{}) {
         log.Println("Key - %v, Value - %v", key, val)
     })
 
     // OrderedRange will iterate over the Map in the sequence in which 
     // elements were added.
+    // Parameter function should not call any methods associated with the map.
     m.OrderedRange(func(key interface{}, val interface{}) {
         log.Println("Key - %v, Value - %v", key, val)
     })