Multithreaded file container?

Question

C++ / C#

How to organize the recording of several sources of binary information into one file?
For clarity, I drew a representation of a certain container:
The length of the container is determined by the time interval.
The number of threads from 0 to N is determined when the container is created.
The completion of the stream(s) is not known, it is necessary to write while the data arrives and the size of the input information satisfies the length of the container.
The "no data" field should not be explicit and have a size, so it should not affect the size of the container .
During the write process, the container can be read by another process, i.e. overwriting should not affect data written earlier .
Container reading is carried out on a specific thread, from a specific timestamp, and should be as linear as possible .
What can you advise for the implementation of this kind of task?

Answer 1

One of the solutions will be in the form of an additional descriptor file for the container, in which the principles of organizing the recorded information will be fixed.
Other suggestions will also be of interest.