chore: modify sample

[joelazar]

This pull request includes several changes to the diam/network_sctp.go and examples/s6a_client/main.go files, focusing on improving SCTP connection handling and enhancing the S6a client example. The most important changes include adding SCTP_NODELAY options, refactoring the S6a client to use a base IMSI and delay between requests, and improving error handling and logging.

SCTP Connection Handling:

• Added Setsockopt calls to enable SCTP_NODELAY to the Dial methods in diam/network_sctp.go to improve performance by disabling Nagle's algorithm. [1] [2]

S6a Client Enhancements:

• Refactored the S6a client example in examples/s6a_client/main.go to use a base IMSI (imsiBase) and added a delay between requests (requestDelay). This allows for better control over the client behavior and improved testing capabilities. [1] [2]
• Modified the sendAIR and sendULR functions to accept an IMSI parameter, allowing dynamic IMSI generation for each request. This helps in simulating multiple unique client requests. [1] [2]
• Enhanced logging and error handling in the S6a client to provide more detailed output and better debugging information. The verbose flag was added to control the verbosity of the logs. [1] [2]

These changes aim to improve the performance, flexibility, and debuggability of the SCTP connections and the S6a client example.