updated documentation (closes #139)

README.md

@@ -668,8 +668,11 @@ Note that a fixed capacity EntityCommandRecorder (or one which has expanded to i
 When needed, an expandable EntityCommandRecorder will double its capacity so it is preferred to use a power of 2 as default capacity.
 
 ```csharp
+// Get a WorldRecord to record entity creation
+WorldRecord worldRecord = recorder.Record(world);
+
 // Create a new Entity defered and give an EntityRecord to record commands on it
-EntityRecord newRecord = recorder.Record(world).CreateEntity();
+EntityRecord newRecord = worldRecord.CreateEntity();
 
 // Register an Entity and give an EntityRecord to record commands on it
 EntityRecord record = recorder.Record(entity);

source/DefaultEcs/System/AEntityMultiMapSystem.cs

@@ -10,6 +10,8 @@ namespace DefaultEcs.System
 {
     /// <summary>
     /// Represents a base class to process updates on a given <see cref="EntityMultiMap{TKey}"/> instance.
+    /// Only <see cref="Entity.Get{T}()"/> operations on already present component type are safe.
+    /// Any other operation maybe change the inner <see cref="EntityMultiMap{TKey}"/> and should be done either by setting "useBuffer" of the available constructors to true or using an <see cref="Command.EntityCommandRecorder"/>.
     /// </summary>
     /// <typeparam name="TState">The type of the object used as state to update the system.</typeparam>
     /// <typeparam name="TKey">The type of the component used as key.</typeparam>

source/DefaultEcs/System/AEntitySetSystem.cs

@@ -8,7 +8,8 @@ namespace DefaultEcs.System
 {
     /// <summary>
     /// Represents a base class to process updates on a given <see cref="EntitySet"/> instance.
-    /// Only <see cref="Entity.Get{T}()"/>, <see cref="Entity.Set{T}(in T)"/> and <see cref="Entity.SetSameAs{T}(in Entity)"/> operation on already present component type are safe.
+    /// Only <see cref="Entity.Get{T}()"/> operations on already present component type are safe.
+    /// Any other operation maybe change the inner <see cref="EntitySet"/> and should be done either by using setting "useBuffer" of the available constructors to true or using an <see cref="Command.EntityCommandRecorder"/>.
     /// </summary>
     /// <typeparam name="T">The type of the object used as state to update the system.</typeparam>
     public abstract class AEntitySetSystem<T> : ISystem<T>

source/DefaultEcs/System/AEntitySortedSetSystem.cs

@@ -8,7 +8,8 @@ namespace DefaultEcs.System
 {
     /// <summary>
     /// Represents a base class to process updates on a given <see cref="EntitySortedSet{TComponent}"/> instance.
-    /// Only <see cref="Entity.Get{T}()"/>, <see cref="Entity.Set{T}(in T)"/> and <see cref="Entity.SetSameAs{T}(in Entity)"/> operation on already present component type are safe.
+    /// Only <see cref="Entity.Get{T}()"/> operations on already present component type are safe.
+    /// Any other operation maybe change the inner <see cref="EntitySortedSet{TComponent}"/> and should be done either by using setting "useBuffer" of the available constructors to true or using an <see cref="Command.EntityCommandRecorder"/>.
     /// </summary>
     /// <typeparam name="TState">The type of the object used as state to update the system.</typeparam>
     /// <typeparam name="TComponent">The type of the component to sort <see cref="Entity"/> by.</typeparam>