I think what you mean by "treading" is reading a line, or chunk, of the file at a time; this is sometimes referred to as "data virtualization." This enables handling very large files that can not be read into memory completely. "Lazy loading" is another term used to describe this strategy.
Obviously, to use this technique the file itself has to be organized in "meaningful chunks."
Here's the MSDN tutorial on reading a File line-by-line: [
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Consider revising your question by adding more information about what you mean by "treading."
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