Read/write nested dictionary under fixed size list in ipc stream reader/write

[viirya]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
This is for nested dictionaries under FixedSizeList in IPC stream reader/writer.

Describe the solution you'd like
IPC stream reader/writer can read/write nested dictionaries in FixedSizeList.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.