Refactor FileStream and HiCFileWriter to be more robust against data races #1238

Job	Run time
Generate job matrix	8s
Cache test dataset / Cache test datasets	7s
Build Conan deps / Build dependencies with Conan (ubuntu-20.04)	38s
Build Conan deps / Build dependencies with Conan (${{ inputs.os }})	0s
Build Conan deps / Build dependencies with Conan (${{ inputs.os }})	0s
Build Conan deps / Collect output	1s
Build project (gcc-8, ubuntu-20.04, Ninja, 3.29.*, Debug, OFF)	18m 54s
Build project (gcc-14, ubuntu-24.04, Ninja, 3.29.*, Debug, ON)	37m 8s
Build project (clang-8, ubuntu-20.04, Ninja, 3.29.*, Debug, OFF)	1m 21s
Build project (clang-18, ubuntu-24.04, Ninja, 3.29.*, Debug, ON)	15m 13s
Build project (gcc-14, ubuntu-24.04, Ninja, 3.29.*, Release, ON)	1h 16m 48s
Build project (clang-18, ubuntu-24.04, Ninja, 3.29.*, Release, ON)	29m 47s
Run unit tests	0s
Run integration tests	0s
Clean stale Ccache cache	0s
Status Check (Ubuntu CI)	1s
	3h 0m 6s

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