public static long signed(InputStream is) throws IOException {
		return read(is, true);
	}
Reads a signed LEB128 variable length integer from the stream.

@param is {@link InputStream} to get bytes from
@return leb128 value, as a long
@throws IOException if an I/O error occurs or decoded value is outside the range of a java
64 bit int (or it used more than {@value #MAX_SUPPORTED_LENGTH} bytes to be encoded), or 
there is an error or EOF getting a byte from the InputStream before reaching the end of the
encoded value
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/LEB128.java