apply
set [a,b):A
set [b,c):B
set [c,d):C
set [d,e):D
set [e,f):D
set [f,g):D
set [g,h):D
----
added [a,b):A
added [b,c):B
added [c,d):C
added [d,e):D
added [e,f):D
added [f,g):D
added [g,h):D

split-keys span=[a,z)
----
key=b
key=c
key=d

apply
delete [e,f)
----
deleted [e,f)

overlapping span=[a,z)
----
[a,b):A
[b,c):B
[c,d):C
[d,e):D
[f,g):D
[g,h):D

split-keys span=[a,z)
----
key=b
key=c
key=d

apply
set [e,f):E
set [f,g):E
----
deleted [f,g)
added [e,f):E
added [f,g):E

overlapping span=[a,z)
----
[a,b):A
[b,c):B
[c,d):C
[d,e):D
[e,f):E
[f,g):E
[g,h):D

interned
----
A (refs = 1)
B (refs = 1)
C (refs = 1)
D (refs = 2)
E (refs = 2)

split-keys span=[a,z)
----
key=b
key=c
key=d
key=e
key=g
