decimal128 - A decimal floating-point number with 34 significant decimal digits
decimal128 format represents a 128-bit decimal floating-point number as defined by IEEE 754 2008 and ISO/IEC/IEEE 60559:2011.
Representation as a JSON string is preferred as this avoids problems with recipients that parse JSON numbers into binary64 memory representation.
String representation allows expressing the special values
INF that cannot be expressed as JSON numbers.