とばかりにAs if (to say), Seeming that

とばかり is a construction that is often used to show that something is being done 'as if to say (A)', or 'seeming that (A)'. It is a combination of the case-marking particle と in its 'quotation' use, and the adverbial particle ばかり, exhibiting that something is 'basically exactly as described'. Due to this, とばかり simply indicates that while (A) is as described, it is not literally the case.

とばかり can appear after almost any word, as the と is creating a quote. に will often follow ばかり when the sentence is going on to describe what is actually happening.

とばかりに is an abbreviation of と言(い)わんばかり 'to only just not be at the point where (A) is said', which itself will still be seen quite often.

In this case, 言(い)わん is an abbreviation of 言(い)わぬ, making use of the classical auxiliary verb ぬ used for negation.

Caution

As とばかりに will be used to describe the way that something 'looks like it is about to say', it won't be used for describing the speaker themselves. However, it may occasionally be seen being used about the speaker if the sentence is in third person.