Suddenly it's not in dribs and drabs (3,2,4)
I believe the answer is:
all at once
'suddenly' is the definition.
(I've seen this before)
'it's not in dribs and drabs' is the wordplay.
I cannot really see how this works, but
an anagram of 'not' is 'ton' which is located in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for all at once that I've seen before include "Simultaneously - immediately" , "Together" , "Without warning" , "How daffodils appeared to Wordsworth" , "in unison" .)