Just creating a stream on the JS heap isn't enough, as we will later
crash when trying to read from that stream as it hasn't been properly
initialized. Instead, until we have teeing implemented (which is a
rather huge part of the Streams spec), create streams using proper AOs
that do initialize the stream.
The JS::Value being passed through is not a bigint, and needs to be
converted using ConvertToInt, as per:
https://webidl.spec.whatwg.org/#es-unsigned-long-long
Furthermore, the IDL definition also specifies that this is associated
with the [EnforceRange] extended attribute.
This makes it actually possible to pass through an autoAllocateChunkSize
to the ReadableStream constructor without it throwing a TypeError.
This test proves the ability of TransformStream to execute
caller supplied code in the flush callback, and have access to
TransformStreamDefaultController.
This test proves the ability of TransformStream to execute
caller supplied code in the start callback, and have access to
TransformStreamDefaultController.
This test proves the ability of TransformStream to execute to execute
caller supplied code in the transform callback that can transform
incoming chunks, and have access to TransformStreamDefaultController.
