Keen to be with state enthusiast (5,6)

I believe the answer is:

eager beaver

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'enthusiast' is the definition.
(thesaurus)

'keen to be with state' is the wordplay.
'keen' becomes 'eager' (I've seen this before).
'with state' becomes 'aver' (I've seen this before. I am not sure about the 'with' bit.**).
'eager'+'be'+'aver'='EAGER BEAVER'

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(Other definitions for eager beaver that I've seen before include "Someone who's (too) enthusiastic about work" , "Enthusiast - zealous person - one too eager to work" , "Keen worker" , "Enthusiastic worker" , "Very keen individual" .)

I've seen this clue in The Telegraph.

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