Cache follow state

develop:

Operating System: Linux
CPU Information: Intel(R) Atom(TM) CPU  C2550  @ 2.40GHz
Number of Available Cores: 4
Available memory: 7.75 GB
Elixir 1.8.2
Erlang 22.0.2

Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 ns
parallel: 1
inputs: none specified
Estimated total run time: 7 s

Benchmarking render_timeline...

Name                      ips        average  deviation         median         99th %
render_timeline          3.86      259.07 ms    ±15.55%      268.17 ms      281.58 ms

this branch:

Operating System: Linux
CPU Information: Intel(R) Atom(TM) CPU  C2550  @ 2.40GHz
Number of Available Cores: 4
Available memory: 7.75 GB
Elixir 1.8.2
Erlang 22.0.2

Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 ns
parallel: 1
inputs: none specified
Estimated total run time: 7 s

Benchmarking render_timeline...

Name                      ips        average  deviation         median         99th %
render_timeline         13.49       74.16 ms     ±4.27%       73.24 ms       84.82 ms

Closes #1180 (closed)