CSHARP-5621: Fix BinaryConnectionTests.ReceiveMessage_should_throw_a_FormatException fails with TimeoutException

[medhatiwari]

Jira Ticket

This PR fixes a test case failure in BinaryConnectionTests.ReceiveMessage_should_throw_a_FormatException_when_message_is_an_invalid_size when run on Big Endian systems like s390x.

Root Cause:
The test uses BitConverter.GetBytes(length) which encodes the integer in system-native endianness. MongoDB’s wire protocol, however, requires that all integer fields be little-endian. When the test runs on a Big Endian system, the message size is encoded incorrectly, leading the driver to misinterpret the message size and wait for more data, resulting in a TimeoutException.

Fix:
fix the test by reversing the byte array explicitly if BitConverter.IsLittleEndian == false. This ensures consistent little-endian encoding regardless of the platform.

Alternative:
Instead of using BitConverter and reversing bytes manually, we could replace the logic with BinaryPrimitives.WriteInt32LittleEndian, which guarantees correct little-endian encoding

Span<byte> bytes = stackalloc byte[4];
BinaryPrimitives.WriteInt32LittleEndian(bytes, length);
stream.Write(bytes);

cc: @giritrivedi

[papafe]

I think there is a spelling mistake here.

[medhatiwari]

Oops, typo indeed, fixed it