Hashgraph 6.0.0

Version 6.0.0 Throw new ContractException for Query Contract Errors

Version 6 introduces two potentially breaking changes. First, the library has removed its dependency on the NSec library. This change has nothing to do with the quality of the NSec library, which has served the project well. However, while adding Smart Contract support to the Hashgraph library, a dependency on the Bouncy Castle project was necessary. Since the Bouncy Castle library also provides Ed25519 support, having references to two security libraries was redundant and the library code was switch to the Bouncy Castle implementation. The associated testing project still relies heavily on the NSec library; and may do so for some time given the ease and utility the NSec library provides in testing.

The second potentially breaking change is the addition of the ContractException class. The behavior of QueryContractAsync method has changed. Previous implementations would throw a PrecheckException for any non-success result returned from the network. However, the network, at times, includes additional error and diagnostics information that cannot be captured in a PrecheckException. The ContractException was introduced to communicate this information back to the calling code. Since the information is nearly identical to a ContractCallResult, and additional flag was also introduced on the QueryContractParams called ThrowOnFail that when set to false, the QueryContractAsync function will always return a ContractCallResult, regardless of call result (in so far as the query request was accepted by the network and not rejected due to an invalid signature or other typical sources of PrecheckExceptions). The default value for ThrowOnFail is true to align more closely with existing behavior.