read stream to end for negative length in writeBinary(InputStream)

[Sahana2524]

Raw exception from writeBinary when stream length is unknown

writeBinary(Base64Variant, InputStream, int) treats a negative dataLength as a real length, but per the JsonGenerator contract a negative value means "length unknown, read to the end of stream", and the JSON backend already handles it that way. The attribute path reaches new byte[dataLength] and the element path a bounded read(..., dataLength), so the call leaves the generator as a raw NegativeArraySizeException / IndexOutOfBoundsException instead of a JacksonException. Reading the stream to the end and then reusing the existing byte[] path (which Stax2 needs for the full-buffer/attribute writes anyway) keeps the output identical to the JSON backend for the same input; non-negative lengths are untouched.

[github-actions]

🧪 Code Coverage Report

Metric	Coverage	Change
Instructions	74.30%	📈 +0.250%
Branches	69.04%	📈 +0.210%

Coverage data generated from JaCoCo test results