a = Pcollect({ |event| (aa:9) }, (zz: 4));
x = a.asStream;
x.next(());

( 'zz': ( 'aa': 9 ) )

a = Pcollect({ |event| event.put(\test, -100) }, (zz: 4));
x = a.asStream;
x.next(());

ERROR: Message 'put' not understood.
RECEIVER:
   Integer 4
ARGS:
   Symbol 'test'
   Integer -100
PATH: /Volumes/data/sc/(this)/devel/devel jitlib/dynamic node proxy/pdef tests.scd
CALL STACK:
    DoesNotUnderstandError:reportError   0x1179a3698
        arg this = <instance of DoesNotUnderstandError>
    Nil:handleError   0x1179a37f8
        arg this = nil
        arg error = <instance of DoesNotUnderstandError>
    Thread:handleError   0x1179a3958
        arg this = <instance of Thread>
        arg error = <instance of DoesNotUnderstandError>
    Object:throw   0x1179a3a08
        arg this = <instance of DoesNotUnderstandError>
    Object:doesNotUnderstand   0x1179a4038
        arg this = 4
        arg selector = 'put'
        arg args = [*2]
    < FunctionDef in Method Dictionary:collect >   0x1179a40e8
        arg key = 'zz'
        arg elem = 4
    Dictionary:keysValuesArrayDo   0x11f2af9b8
        arg this = <instance of Event>
        arg argArray = [*4]
        arg function = <instance of Function>
        var i = 0
        var j = 1
        var key = nil
        var val = nil
        var arraySize = nil
    Dictionary:keysValuesDo   0x1179a4198
        arg this = <instance of Event>
        arg function = <instance of Function>
    Dictionary:collect   0x1179a45b8
        arg this = <instance of Event>
        arg function = <instance of Function>
        var res = <instance of Event>
    < closed FunctionDef >  (no arguments or variables)
    Interpreter:interpretPrintCmdLine   0x11f2af628
        arg this = <instance of Interpreter>
        var res = nil
        var func = <instance of Function>
        var code = "x = a.asStream;"
        var doc = nil
        var ideClass = <instance of Meta_ScIDE>
    Process:interpretPrintCmdLine   0x1179a4d48
        arg this = <instance of Main>
^^ The preceding error dump is for ERROR: Message 'put' not understood.
RECEIVER: 4