The most common and most likely answer to this crossword clue is the 10 letter word SERIALISED
I've seen this crossword clue in The Guardian
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More clues leading to the result SERIALISED
Buddy explains!
The straight part
We know that "one bit at a time" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one bit at a time = serialised.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SERIALISED mean?
SERIALISED verb- To convert an object into a sequence of bytes that can later be converted back into an object with equivalent properties.
- To write a television program, novel, or other form of entertainment as a sequence of shorter works with a common story.